Portable camera with an ink jet printer and cutting blade

ABSTRACT

A portable camera system comprising an image sensor device for sensing an image; a processing means for processing the sensed image; a print media supply means provided for the storage of print media in a roll form; a print head for printing the sensed image on print media stored internally to the camera system; and a cutter mechanism for cutting the printed sensed images comprising a worm screw extending the length of the printed sensed image; and a worm gear attached to the worm screw and adapted to be driven the length of the printed sensed image, the worm gear including a cutting blade for cutting the print media into separate sheets. The cutting blade can comprise a rotatable wheel having a sharpened outer edge and the cogged wheel can have a series of usage indicators printed on one surface thereof and the worm gear can includes a lever arm wherein the traversal of the worm gear along the length of the printed sensed image results in the engagement of the lever arm with the cogged wheel print indicator so as to rotate the cogged wheel print indicator so that it maintains a current indication of the number of images printed out on the print media. The camera can further comprise a pawl mechanism which interacts with the coggs of the cogged wheel print indicator in the form of a rachet and pawl mechanism and the lever arm can includes a flexible portion for engagement with the cogged wheel print indicator.

REFERENCES TO RELATED APPLICATIONS

The following co-pending U.S. patent applications, identified by their U.S. patent application Ser. Nos. (USSN), were filed simultaneously to the present application on Jul. 10, 1998, and are hereby incorporated by cross-reference: 09/113,060; 09/113,070; 09/113,073; 09/112,748; 09/112,747; 09/112,776; 09/112,750; 09/112,746; 09/112,743; 09/112,742; 09/112,741; 09/112,740; 09/112,739; 09/113,053; 09/112,738; 09/113,067; 09/113,063; 09/113,069; 09/112,744; 09/113,058; 09/112,777; 09/113,224; 09/112,804; 09/112,805; 09/113,072; 09/112,785; 09/112,797; 09/112,796; 09/113,071; 09/112,824; 09/113,090; 09/112,823; 09/113,222; 09/112,786; 09/113,051; 09/112,782; 09/113,056; 09/113,059; 09/113,091; 09/112,753; 09/113,055; 09/113,057; 09/113,054; 09/112,752; 09/112,759; 09/112,757; 09/112,758; 09/113,107; 09/112,829; 09/112,792; 09/112,791; 09/112,790; 09/112,789; 09/112,788; 09/112,795; 09/112,749; 09/112,784; 09/112,783; 09/112,763; 09/112,762; 09/112,737; 09/112,761; 09/113,223; 09/112,781; 09/113,052; 09/112,834; 09/113,103; 09/113,101; 09/112,751; 09/112,787; 09/112,802; 09/112,803; 09/113,097; 09/113,099; 09/113,084; 09/113,066; 09/112,778; 09/112,779; 09/113,077; 09/113,061; 09/112,818; 09/112,816; 09/112,772; 09/112,819; 09/112,815; 09/113,096; 09/113,068; 09/113,095; 09/112,808; 09/112,809; 09/112,780; 09/113,083; 09/113,121; 09/113,122; 09/112,793; 09/112,794; 09/113,128; 09/113,127; 09/112,756; 09/112,755; 09/112,754; 09/112,811; 09/112,812; 09/112,813; 09/112,814; 09/112,764; 09/112,765; 09/112,767; 09/112,768; 09/112,807; 09/112,806; 09/112,820; 09/112,821; 09/112,822; 09/112,825; 09/112,826; 09/112,827; 09/112,828; 09/113,111; 09/113,108; 09/113,109; 09/113,123; 09/113,114; 09/113,115; 09/113,129; 09/113,124; 09/113,125; 09/113,126; 09/113,119; 09/113,120; 09/113,221; 09/113,116; 09/113,118; 09/113,117; 09/113,113; 09/113,130; 09/113,110; 09/113,112; 09/113,087; 09/113,074; 09/113,089; 09/113,088; 09/112,771; 09/112,769; 09/112,770; 09/112,817; 09/113,076; 09/112,798; 09/112,801; 09/112,800; 09/112,799; 09/113,098; 09/112,833; 09/112,832; 09/112,831; 09/112,830; 09/112,836; 09/112,835; 09/113,102; 09/113,106; 09/113,105; 09/113,104; 09/112,810; 09/112,766; 09/113,085; 09/113,086; 09/113,094; 09/112,760; 09/112,773; 09/112,774; 09/112,775; 09/112,745; 09/113,092; 09/113,100; 09/113,093; 09/113,062; 09/113,064; 09/113,082; 09/113,081; 09/113,080; 09/113,079; 09/113,065; 09/113,078; 09/113,075.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

The present relates substantially to the concept of a disposable camera having instant printing capabilities and in particular, discloses An Apparatus for Automated Photo Counting.

BACKGROUND OF THE INVENTION

Recently, the concept of a "single use" disposable camera has become an increasingly popular consumer item. Disposable camera systems presently on the market normally includes an internal film roll and a simplified gearing mechanism for traversing the film roll across an imaging system including a shutter and lensing system. The user, after utilising a single film roll returns the camera system to a film development center for processing. The film roll is taken out of the camera system and processed and the prints returned to the user. The camera system is then able to be re-manufactured through the insertion of a new film roll into the camera system, the replacement of any worn or wearable parts and the re-packaging of the camera system in accordance with requirements. In this way, the concept of a single use "disposable" camera is provided to the consumer.

Recently, a camera system has been proposed by the present applicant which provides for a handheld camera device having an internal printhead, image sensor and processing means such that images sensed by the image sensing means, are processed by the processing means and adapted to be instantly printed out by the printing means on demand. The proposed camera system further discloses a system of internal "print rolls" carrying print media such as film on to which images are to be printed in addition to ink to supply to the printing means for the printing process. The print roll is further disclosed to be detachable and replaceable within the camera system.

Unfortunately, such a system is likely to only be constructed at a substantial cost and it would be desirable to provide for a more inexpensive form of instant camera system which maintains a substantial number of the quality aspects of the aforementioned arrangement.

In particular, in any "disposable camera" it would be desirable to provide for a simple and rapid form of replenishment of the consumable portions in any disposable camera so that the disposable camera can be readily and rapidly serviced by replenishment and returned to the market place.

It would be further desirable to provide for a simplified form of automated picture counting in a disposable camera system.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide for an efficient and effective operation of a picture counting system in a print on demand camera system.

In accordance with a first aspect of the present invention, there is provided a portable camera system comprising an image sensor device for sensing an image; a processing means for processing the sensed image; a print media supply means provided for the storage of print media in a roll form; a printhead for printing the sensed image on print media stored internally to the camera system; and a cutter mechanism for cutting the printed sensed images comprising a worm screw extending the length of the printed sensed image; and a worm gear attached to the worm screw and adapted to be driven the length of the printed sensed image, the worm gear including a cutting blade for cutting the print media into separate sheets;

The cutting blade can comprise a rotatable wheel having a sharpened outer edge and the cogged wheel can have a series of usage indicators printed on one surface thereof and the worm gear can includes a lever arm wherein the traversal of the worm gear along the length of the printed sensed image results in the engagement of the lever arm with the cogged wheel print indicator so as to rotate the cogged wheel print indicator so that it maintains a current indication of the number of images printed out on the print media.

The camera can further comprise a pawl mechanism which interacts with the coggs of the cogged wheel print indicator in the form of a rachet and pawl mechanism and the lever arm can includes a flexible portion for engagement with the cogged wheel print indicator.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 illustrates a side front perspective view of the assembled camera of the preferred embodiment;

FIG. 2 illustrates a back side perspective view, partly exploded, of the preferred embodiment;

FIG. 3 is a side perspective view of the chassis of the preferred embodiment;

FIG. 4 is a side perspective view of the chassis illustrating the insertion of the electric motors;

FIG. 5 is an exploded perspective of the ink supply mechanism of the preferred embodiment;

FIG. 6 is a side perspective of the assembled form of the ink supply mechanism of the preferred embodiment;

FIG. 7 is a front perspective view of the assembled form of the ink supply mechanism of the preferred embodiment;

FIG. 8 is an exploded perspective of the platen unit of the preferred embodiment;

FIG. 9 is a side perspective view of the assembled form of the platen unit;

FIG. 10 is also a perspective view of the assembled form of the platen unit;

FIG. 11 is an exploded perspective unit of a printhead recapping mechanism of the preferred embodiment;

FIG. 12 is a close up exploded perspective of the recapping mechanism of the preferred embodiment;

FIG. 13 is an exploded perspective of the ink supply cartridge of the preferred embodiment;

FIG. 14 is a close up perspective, partly in section, of the internal portions of the ink supply cartridge in an assembled form;

FIG. 15 is a schematic block diagram of one form of chip layer of the image capture and processing chip of the preferred embodiment;

FIG. 16 is an exploded perspective illustrating the assembly process of the preferred embodiment;

FIG. 17 illustrates a front exploded perspective view of the assembly process of the preferred embodiment;

FIG. 18 illustrates a side perspective view of the assembly process of the preferred embodiment;

FIG. 19 illustrates a side perspective view of the assembly process of the preferred embodiment;

FIG. 20 is a perspective view illustrating the insertion of the platen unit in the preferred embodiment;

FIG. 21 illustrates the interconnection of the electrical components of the preferred embodiment;

FIG. 22 illustrates the process of assembling the preferred embodiment; and

FIG. 23 is a perspective view further illustrating the assembly process of the preferred embodiment.

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

Turning initially simultaneously to FIG. 1, and FIG. 2 there is illustrated perspective views of an assembled camera constructed in accordance with the preferred embodiment with FIG. 1 showing a front side perspective view and FIG. 2 showing a back side perspective view. The camera 1 includes a paper or plastic film jacket 2 which can include simplified instructions 3 for the operation of the camera system 1. The camera system 1 includes a first "take" button 4 which is depressed to capture an image. The captured image is output via output slot 6. A further copy of the image can be obtained through depressing a second "printer copy" button 7 whilst an LED light 5 is illuminated. The camera system also provides the usual view finder 8 in addition to a CCD image capture/lensing system 9.

The camera system 1 provides for a standard number of output prints after which the camera system 1 ceases to function. A prints left indicator slot 10 is provided to indicate the number of remaining prints. A refund scheme at the point of purchase is assumed to be operational for the return of used camera systems for recycling.

Turning now to FIG. 3, the assembly of the camera system is based around an internal chassis 12 which can be a plastic injection molded part. A pair of paper pinch rollers 28, 29 utilized for decurling are snap fitted into corresponding frame holes eg. 26, 27.

As shown in FIG. 4, the chassis 12 includes a series of mutually opposed prongs eg. 13, 14 into which is snapped fitted a series of electric motors 16, 17. The electric motors 16, 17 can be entirely standard with the motor 16 being of a stepper motor type and include a cogged end portion 19, 20 for driving a series of gear wheels. A first set of gear wheels is provided for controlling a paper cutter mechanism and a second set is provided for controlling print roll movement.

Turning next to FIGS. 5 to 7, there is illustrated an ink supply mechanism 40 utilized in the camera system. FIG. 5 illustrates a back exploded perspective view, FIG. 6 illustrates a back assembled view and FIG. 7 illustrates a front assembled view. The ink supply mechanism 40 is based around an ink supply cartridge 42 which contains printer ink and a printhead mechanism for printing out pictures on demand. The ink supply cartridge 42 includes a side aluminium strip 43 which is provided as a shear strip to assist in cutting images from a paper roll.

A dial mechanism 44 is provided for indicating the number of "prints left". The dial mechanism 44 is snap fitted through a corresponding mating portion 46 so as to be freely rotatable.

As shown in FIG. 6, the printhead includes a flexible PCB strip 47 which interconnects with the printhead and provides for control of the printhead. The interconnection between the flexible PCB strip and an image sensor and printhead chip can be via Tape Automated Bonding (TAB) Strips 51, 58. A moulded aspherical lens and aperture shim 50 (FIG. 5) is also provided for imaging an image onto the surface of the image sensor chip normally located within cavity 53 and a light box module or hood 52 is provided for snap fitting over the cavity 53 so as to provide for proper light control. A series of decoupling capacitors eg. 34 can also be provided. Further, a plug 121 (FIG. 7) is provided for re-plugging ink holes after refilling. A series of guide prongs eg. 55-57 are further provided for guiding the flexible PCB strip 47.

The ink supply mechanism 40 interacts with a platen unit 60 which guides print media under a printhead located in the ink supply mechanism. FIG. 8 shows an exploded view of the platen unit 60, while FIGS. 9 and 10 show assembled views of the platen unit 60. The platen unit 60 includes a first pinch roller 61 which is snap fitted to one side of a platen base 62. Attached to a second side of the platen base 62 is a cutting mechanism 63 which traverses the platen by means of a rod 64 having a screwed thread which is rotated by means of cogged wheel 65 which is also fitted to the platen 62. The screwed thread engages a block 67 which includes a cutting wheel 68 fastened via a fastener 69. Also mounted to the block 67 is a counter actuator which includes a prong 71. The prong 71 acts to rotate the dial mechanism 44 of FIG. 6 upon the return traversal of the cutting wheel. As shown previously in FIG. 6, the dial mechanism 44 includes a cogged surface which interacts with pawl lever 73, thereby maintaining a count of the number of photographs taken on the surface of dial mechanism 44. The cutting mechanism 63 is inserted into the platen base 62 by means of a snap fit via receptacle 74.

The platen 62 includes an internal re-capping mechanism 80 for re-capping the printhead when not in use. The re-capping mechanism 80 includes a sponge portion 81 and is operated via a solenoid coil so as to provide for recapping of the printhead. In the preferred embodiment, there is provided an inexpensive form of printhead re-capping mechanism provided for incorporation into a handheld camera system so as to provide for printhead re-capping of an inkjet printhead.

FIG. 11 illustrates an exploded view of the recapping mechanism 80 whilst FIG. 12 illustrates a close up of the end portion thereof. The re-capping mechanism 80 is structured around a solenoid including a 16 turn coil 75 which can comprise insulated wire. The coil 75 is turned around a first stationary solenoid arm 76 which is mounted on a bottom surface of the platen 62 (FIG. 8) and includes a post portion 77 to magnify effectiveness of operation. The arm 76 can comprise a ferrous material.

A second moveable arm 78 of the solenoid actuator is also provided, the arm 78 is moveable and is also made of ferrous material. Mounted on the arm is a sponge portion surrounded by an elastomer strip 79. The elastomer strip 79 is of a generally arcuate cross-section and acts as a leaf spring against the surface of the printhead ink supply cartridge 42 (FIG. 5) so as to provide for a seal against the surface of the printhead ink supply cartridge 42. In the quiescent position elastomer spring units 87, 88 act to resiliently deform the elastomer seal 79 against the surface of the ink supply unit 42.

When it is desired to operate the printhead unit upon the insertion of paper, the solenoid coil 75 is activated so as to cause the arm 78 to move down to be adjacent to the end plate 76. The arm 78 is held against end plate 76 while the printhead is printing by means of a small "keeper current" in coil 75. Simulation results indicate that the keeper current can be significantly less than the actuation current. Subsequently, after photo printing, the paper is guillotined by the cutting mechanism 63 of FIG. 8 acting against Aluminium Strip 43 of FIG. 5, and rewound so as to clear the area of the re-capping mechanism 80. Subsequently, the current is turned off and springs 87, 88 return the arm 78 so that the elastomer seal is again resting against the printhead ink supply cartridge.

It can be seen that the preferred embodiment provides for a simple and inexpensive means of re-capping a printhead through the utilisation of a solenoid type device having a long rectangular form. Further, the preferred embodiment utilises minimal power in that currents are only required whilst the device is operational and additionally, only a low keeper current is required whilst the printhead is, printing.

Turning next to FIG. 13 and 14, FIG. 13 illustrates an exploded perspective of the ink supply cartridge 42 whilst FIG. 14 illustrates a close up sectional view of a bottom of the ink supply cartridge 42 with the printhead unit in place. The ink supply cartridge 42 is based around a pagewidth printhead 102 which comprises a long slither of silicon having a series of holes etched on the back surface for the supply of ink to a front surface of the silicon wafer for subsequent ejection via a micro electro mechanical system. The form of ejection can be many different forms such as those set out in the tables below.

Of course, many other inkjet technologies, as referred to the attached tables below, can also be utilised when constructing a printhead unit 102. The fundamental requirement of the ink supply cartridge 42 being the supply of ink to a series of color channels etched through the back surface of the printhead 102. In the description of the preferred embodiment, it is assumed that a three color printing process is to be utilised so as to provide full color picture output. Hence, the ink supply unit 42 includes three ink supply reservoirs being a cyan reservoir 104, a magenta reservoir 105 and a yellow reservoir 106. Each of these reservoirs is configured to store ink and includes a corresponding sponge type material 107-109 which assists in stabilising ink within the corresponding ink channel and therefore preventing the ink from sloshing back and forth when the printhead is utilised in a handheld camera system. The reservoirs 104, 105, 106 are formed through the mating of first exterior plastic piece 10 mating with a second base piece) 111.

A first end of the base piece 111 includes a series of air inlets 113-115. The air inlets lead to a corresponding winding channel which is hydrophobically treated so as to act as an ink repellent and therefore repel any ink that may flow along the air inlet channel. The air inlet channel rather takes a convoluted path further assisting in resisting any ink flow out of the chambers 104-106. An adhesive tape portion 117 is provided for sealing the channels within end portion 118.

At the top end, there is included a series of refill holes for refilling corresponding ink supply chambers 104, 105, 106. A plug 121 is provided for sealing the refill holes.

Turning now to FIG. 14, there is illustrated a close up perspective view, partly in section, through the ink supply cartridge 42 of FIG. 13 when formed as a unit. The ink supply cartridge includes the three color ink reservoirs 104, 105, 106 which supply ink to different portions of the back surface of printhead 102 which includes a series of apertures 128 defined therein for carriage of the ink to the front surface.

The ink supply unit includes two guide walls 124, 125 which separate the various ink chambers and are tapered into an end portion abutting the surface of the printhead 102. The guide walls are further mechanically supported at regular spaces by block portions 126 which are placed at regular intervals along the length of the printhead supply unit. The block portions 126 leave space at portions close to the back of printhead 102 for the flow of ink around the back surface thereof.

The printhead supply unit is preferably formed from a multi-part plastic injection mold and the mold pieces eg. 110, 111 (FIG. 13) snap together around the sponge pieces 107, 108, 109. Subsequently, a syringe type device can be inserted in the ink refill holes and the ink reservoirs filled with ink with the air flowing out of the air outlets 113-115. Subsequently, the adhesive tape portion 117 and plug 121 are attached and the printhead tested for operation capabilities. Subsequently, the ink supply cartridge 42 can be readily removed for refilling by means of removing the ink supply cartridge, performing a washing cycle, and then utilising the holes for the insertion of a refill syringe filled with ink for refilling the ink chamber before returning the ink supply cartridge 42 to a camera.

Turning now to FIG. 15, there is shown an example layout of the Image Capture and Processing Chip (ICP) 48.

The Image Capture and Processing Chip 48 provides most of the electronic functionality of the camera with the exception of the printhead chip. The chip 48 is a highly integrated system. It combines CMOS image sensing, analog to digital conversion, digital image processing, DRAM storage, ROM, and miscellaneous control functions in a single chip.

The chip is estimated to be around 32 mm² using a leading edge 0.18 micron CMOS/DRAM/APS process. The chip size and cost can scale somewhat with Moore's law, but is dominated by a CMOS active pixel sensor array 201, so scaling is limited as the sensor pixels approach the diffraction limit.

The ICP 48 includes CMOS logic, a CMOS image sensor, DRAMA and analog circuitry. A very small amount of flash memory or other non-volatile memory is also preferably included for protection against reverse engineering.

Alternatively, the ICP can readily be divided into two chips: one for the CMOS imaging array, and the other for the remaining circuitry. The cost of this two chip solution should not be significantly different than the single chip ICP, as the extra cost of packaging and bond-pad area is somewhat cancelled by the reduced total wafer area requiring the color filter fabrication steps. The ICP preferably contains the following functions:

    ______________________________________                                         Function                                                                       ______________________________________                                                1.5 megapixel image sensor                                                     Analog Signal Processors                                                       Image sensor column decoders                                                   Image sensor row decoders                                                      Analogue to Digital Conversion (ADC)                                           Column ADC's                                                                   Auto exposure                                                                  12 Mbits of DRAM                                                               DRAM Address Generator                                                         Color interpolator                                                             Convolver                                                                      Color ALU                                                                      Halftone matrix ROM                                                            Digital halftoning                                                             Printhead interface                                                            8 bit CPU core                                                                 Program ROM                                                                    Flash memory                                                                   Scratchpad SRAM                                                                Parallel interface (8 bit)                                                     Motor drive transistors (5)                                                    Clock PLL                                                                      JTAG test interface                                                            Test circuits                                                                  Busses                                                                         Bond pads                                                               ______________________________________                                    

The CPU, DRAK Image sensor, ROM, Flash memory, Parallel interface, JTAG interface and ADC can be vendor supplied cores. The ICP is intended to run on 1.5 V to minimize power consumption and allow convenient operation from two AA type battery cells.

FIG. 15 illustrates a layout of the ICP 48. The ICP 48 is dominated by the imaging array 201, which consumes around 80% of the chip area. The imaging array is a CMOS 4 transistor active pixel design with a resolution of 1,500×1,000. The array can be divided into the conventional configuration, with two green pixels, one red pixel, and one blue pixel in each pixel group. There are 750×500 pixel groups in the imaging array.

The latest advances in the field of image sensing and CMOS image sensing in particular can be found in the October, 1997 issue of IEEE Transactions on Electron Devices and, in particular, pages 1689 to 1968. Further, a specific implementation similar to that disclosed in the present application is disclosed in Wong et. al, "CMOS Active Pixel Image Sensors Fabricated Using a 1.8 V, 0.25 μm CMOS Technology", IEDM 1996, page 915.

The imaging array uses a 4 transistor active pixel design of a standard configuration. To minimize chip area and therefore cost, the image sensor pixels should be as small as feasible with the technology available. With a four transistor cell, the typical pixel size scales as 20 times the lithographic feature size. This allows a minimum pixel area of around 3.6 μm×3.6 μm. However, the photosite must be substantially above the diffraction limit of the lens. It is also advantageous to have square photosite, to maximize the margin over the diffraction limit in both horizontal and vertical directions. In this case, the photosite can be specified as 2.5 μm×2.5 μm. The photosite can be a photogate, pinned photodiode, charge modulation device, or other sensor.

The four transistors are packed as an `L` shape, rather than a rectangular region, to allow both the pixel and the photosite to be square. This reduces the transistor packing density slightly, increasing pixel size. However, the advantage in avoiding the diffraction limit is greater than the small decrease in packing density.

The transistors also have a gate length which is longer than the minimum for the process technology. These have been increased from a drawn length of 0.18 micron to a drawn length of 0.36 micron. This is to improve the transistor matching by making the variations in gate length represent a smaller proportion of the total gate length.

The extra gate length, and the `L` shaped packing, mean that the transistors use more area than the minimum for the technology. Normally, around 8 μm² would be required for rectangular packing. Preferably, 9.75 μm² has been allowed for the transistors.

The total area for each pixel is 16 μm², resulting from a pixel size of 4 μm×4 μm. With a resolution of 1,500×1,000, the area of the imaging array 101 is 6,000 μm×4,000 μm, or 24 mm².

The presence of a color image sensor on the chip affects the process required in two major ways:

The CMOS fabrication process should be optimized to minimize dark current.

Color filters are required. These can be fabricated using dyed photosensitive polyimides, resulting in an added process complexity of three spin coatings, three photolithographic steps, three development steps, and three hardbakes.

There are 15,000 analog signal processors (ASPs) 205, one for each of the columns of the sensor. The ASPs amplify the signal, provide a dark current reference, sample and hold the signal, and suppress the fixed pattern noise (FPN).

There are 375 analog to digital converters 206, one for each four columns of the sensor array. These may be delta-sigma or successive approximation type ADC's. A row of low column ADC's are used to reduce the conversion speed required, and the amount of analog signal degradation incurred before the signal is converted to digital. This also eliminates the hot spot (affecting local dark current) and the substrate coupled noise that would occur if a single high speed ADC was used. Each ADC also has two four bit DAC's which trim the offset and scale of the ADC to further reduce FPN variations between columns. These DAC's are controlled by data stored in flash memory during chip testing.

The column select logic 204 is a 1:1500 decoder which enables the appropriate digital output of the ADCs onto the output bus. As each ADC is shared by four columns, the least significant two bits of the row select control 4 input analog multiplexors.

A row decoder 207 is a 1:1000 decoder which enables the appropriate row of the active pixel sensor array. This selects which of the 1000 rows of the imaging array is connected to analog signal processors. As the rows are always accessed in sequence, the row select logic can be implemented as a shift register.

An auto exposure system 208 adjusts the reference voltage of the ADC 205 in response to the maximum intensity sensed during the previous frame period. Data from the green pixels is passed through a digital peak detector. The peak value of the image frame period before capture (the reference frame) is provided to a digital to analogue converter(DAC), which generates the global reference voltage for the column ADCs. The peak detector is reset at the beginning of the reference frame. The minimum and maximum values of the three RGB color components are also collected for color correction.

The second largest section of the chip is consumed by a DRAM 210 used to hold the image. To store the 1,500×1,000 image from the sensor without compression, 1.5 Mbytes of DRAM 210 are required. This equals 12 Mbits, or slightly less than 5% of a 256 Mbit DRAM The DRAM technology assumed is of the 256 Mbit generation implemented using 0.18 μm CMOS.

Using a standard 8 F cell, the area taken by the memory array is 3.11 mm². When row decoders, column sensors, redundancy, and other factors are taken into account, the DRAM requires around 4 mm².

This DRAM 210 can be mostly eliminated if analog storage of the image signal can be accurately maintained in the CMOS imaging array for the two seconds required to print the photo. However, digital storage of the image is preferable as it is maintained without degradation, is insensitive to noise, and allows copies of the photo to be printed considerably later.

A DRAM address generator 211 provides the write and read addresses to the DRAM 210. Under normal operation, the write address is determined by the order of the data read from the CMOS image sensor 201. This will typically be a simple raster format. However, the data can be read from the sensor 201 in any order, if matching write addresses to the DRAM are generated. The read order from the DRAM 210 will normally simply match the requirements of a color interpolator and the printhead. As the cyan, magenta, and yellow rows of the printhead are necessarily offset by a few pixels to allow space for nozzle actuators, the colors are not read from the DRAM simultaneously. However, there is plenty of time to read all of the data from the DRAM many times during the printing process. This capability is used to eliminate the need for FEFOs in the printhead interface, thereby saving chip area. All three RGB image components can be read from the DRAM each time color data is required. This allows a color space converter to provide a more sophisticated conversion than a simple linear RGB to CMY conversion.

Also, to allow two dimensional filtering of the image data without requiring line buffers, data is re-read from the DRAM array.

The address generator may also implement image effects in certain models of camera. For example, passport photos are generated by a manipulation of the read addresses to the DRAM. Also, image framing effects (where the central image is reduced), image warps, and kaleidoscopic effects can all be generated by manipulating the read addresses of the DRAM.

While the address generator 211 may be implemented with substantial complexity if effects are built into the standard chip, the chip area required for the address generator is small, as it consists only of address counters and a moderate amount of random logic.

A color interpolator 214 converts the interleaved pattern of red, 2×green, and blue pixels into RGB pixels. It consists of three 8 bit adders and associated registers. The divisions are by either 2 (for green) or 4 (for red and blue) so they can be implemented as fixed shifts in the output connections of the adders.

A convolver 215 is provided as a sharpening filter which applies a small convolution kernel (5×5) to the red, green, and blue planes of the image. The convolution kernel for the green plane is different from that of the red and blue planes, as green has twice as many samples. The sharpening filter has five functions:

To improve the color interpolation from the linear interpolation provided by the color interpolator, to a close approximation of a sinc interpolation.

To compensate for the image `softening` which occurs during digitization.

To adjust the image sharpness to match average consumer preferences, which are typically for the image to be slightly sharper than reality. As the single use camera is intended as a consumer product, and not a professional photographic products, the processing can match the most popular settings, rather than the most accurate.

To suppress the sharpening of high frequency (individual pixel) noise. The function is similar to the `unsharp mask` process.

To antialias Image Warping.

These functions are all combined into a single convolution matrix. As the pixel rate is low (less than 1 Mpixel per second) the total number of multiplies required for the three color channels is 56 million multiplies per second. This can be provided by a single multiplier. Fifty bytes of coefficient ROM are also required.

A color ALU 113 combines the functions of color compensation and color space conversion into the one matrix multiplication, which is applied to every pixel of the frame. As with sharpening, the color correction should match the most popular settings, rather than the most accurate.

A color compensation circuit of the color ALU provides compensation for the lighting of the photo. The vast majority of photographs are substantially improved by a simple color compensation, which independently normalizes the contrast and brightness of the three color components.

A color look-up table (CLUT) 212 is provided for each color component. These are three separate 256×8 SRAMs, requiring a total of 6,144 bits. The CLUTs are used as part of the color correction process. They are also used for color special effects, such as stochastically selected "wild color" effects.

A color space conversion system of the color ALU converts from the ROB color space of the image sensor to the CMY color space of the printer. The simplest conversion is a 1's complement of the RGB data. However, this simple conversion assumes perfect linearity of both color spaces, and perfect dye spectra for both the color filters of the image sensor, and the ink dyes. At the other extreme is a tri-linear interpolation of a sampled three dimensional arbitrary transform table. This can effectively match any nonlinearity or differences in either color space. Such a system is usually necessary to obtain good color space conversion when the print engine work on the color electrophotographic principle.

However, since the non-linearity of a halftoned ink jet output is very small, a simpler system can be used. A simple matrix multiplier can provide excellent results. This requires nine multiplications and six additions per contone pixel. However, since the contone pixel rate is low (less than 1 Mpixel/sec) these operations can share a single multiplier and adder. The multiplier and adder are used in a color ALU which is shared with the color compensation function.

Digital halftoning can be performed as a dispersed dot ordered dither using a stochastic, optimized dither cell. A halftone matrix ROM 116 is provided for storing dither cell coefficients. A dither cell size of 32×32 is adequate to ensure that the cell repeat cycle is not visible. The three colors--cyan, magenta, and yellow--are all dithered using the same cell, to ensure maximum co-positioning of the ink dots. This minimizes `muddying` of the mid-tones which results from bleed of dyes from one dot to adjacent dots while still wet. The total ROM size required is 1 KByte, as the one ROM is shared by the halftoning units for each of the three colors.

The digital halftoning used is dispersed dot ordered dither with stochastic optimized dither matrix. While dithering does not produce an image quite as `sharp` as error diffusion, it does produce a more accurate image with fewer artifacts. The image sharpening produced by error diffusion is artificial, and less controllable and accurate than `unsharp mask` filtering performed in the contone domain. The high print resolution (1,600 dpi×1,600 dpi) results in excellent quality when using a well formed stochastic dither matrix.

Digital halftoning is performed by a digital halftoning unit 217 using a simple comparison between the contone information from the DRAM 210 and the contents of the dither matrix 216. During the halftone process, the resolution of the image is changed from the 250 dpi of the captured contone image to the 1,600 dpi of the printed image. Each contone pixel is converted to an average of 40.96 halftone dots.

The ICP incorporates a 16 bit microcontroller CPU core 219 to run the miscellaneous camera functions, such as reading the buttons, controlling the motor and solenoids, setting up the hardware, and authenticating the refill station. The processing power required by the CPU is very modest, and a wide variety of processor cores can be used. As the entire CPU program is run from a small ROM 220. Program compatibility between camera versions is not important, as no external programs are run. A 2 Mbit (256 Kbyte) program and data ROM 220 is included on chip. Most of this ROM space is allocated to data for outline graphics and fonts for specialty cameras. The program requirements are minor. The single most complex task is the encrypted authentication of the refill station. The ROM requires a single transistor per bit.

A Flash memory 221 may be used to store a 128 bit authentication code. This provides higher security than storage of the authentication code in ROM, as reverse engineering can be made essentially impossible. The Flash memory is completely covered by third level metal, making the data impossible to extract using scanning probe microscopes or electron beams. The authentication code is stored in the chip when manufactured. At least two other Flash bits are required for the authentication process: a bit which locks out reprogramming of the authentication code, and a bit which indicates that the camera has been refilled by an authenticated refill station. The flash memory can also be used to store FPN correction data for the imaging array. Additionally, a phase locked loop resealing parameter is provided for scaling the clocking cycle to an appropriate correct time. The clock frequency does not require crystal accuracy since no date functions are provided. To eliminate the cost of a crystal, an on chip oscillator with a phase locked loop 224 is used. As the frequency of an on-chip oscillator is highly variable from chip to chip, the frequency ratio of the oscillator to the PLL is digitally trimmed during initial testing. The value is stored in Flash memory 221. This allows the clock PLL to control the ink-jet heater pulse width with sufficient accuracy.

A scratchpad SRAM is a small static RAM 222 with a 6T cell. The scratchpad provided temporary memory for the 16 bit CPU. 1024 bytes is adequate.

A printhead interface 223 formats the data correctly for the printhead. The printhead interface also provides all of the timing signals required by the printhead. These timing signals may vary depending upon temperature, the number of dots printed simultaneously, the print medium in the print roll, and the dye density of the ink in the print roll.

The following is a table of external connections to the printhead interface:

    ______________________________________                                         Connection Function               Pins                                         ______________________________________                                         DataBits[0-7]                                                                             Independent serial data to the eight segments                                                         8                                                       of the printhead                                                    BitClock   Main data clock for the printhead                                                                     1                                            ColorEnable[0-2]                                                                          Independent enable signals for the CMY                                                                3                                                       actuators, allowing different pulse times                                      for each color.                                                     BankEnable[0-1]                                                                           Allows either simultaneous or interleaved                                                             2                                                       actuation of two banks of nozzles. This                                        allows two different print speed/power                                         consumption tradeoffs                                               NozzleSelect[0-4]                                                                         Selects one of 32 banks of nozzles for                                                                5                                                       simultaneous actuation                                              ParallelXferClock                                                                         Loads the parallel transfer register with                                                             1                                                       the data from the shift registers                                   Total                             20                                           ______________________________________                                    

The printhead utilized is composed of eight identical segments, each 1.25 cm long. There is no connection between the segments on the printhead chip. Any connections required are made in the external TAB bonding film, which is double sided. The division into eight identical segments is to simplify lithography using wafer steppers. The segment width of 1.25 cm fits easily into a stepper field. As the printhead chip is long and narrow (10 cm×0.3 mm), the stepper field contains a single segment of 32 printhead chips. The stepper field is therefore 1.25 cm×1.6 cm. An average of four complete printheads are patterned in each wafer step.

A single BitClock output line connects to all 8 segments on the printhead. The 8 DataBits lines lead one to each segment, and are clocked in to the 8 segments on the printhead simultaneously (on a BitClock pulse). For example, dot 0 is transferred to segments, dot 750 is transferred to segment, dot 1500 to segment₂ etc simultaneously.

The ParallelXferClock is connected to each of the 8 segments on the printhead, so that on a single pulse, all segments transfer their bits at the same time.

The NozzleSelect, BankEnable and ColorEnable lines are connected to each of the 8 segments, allowing the printhead interface to independently control the duration of the cyan, magenta, and yellow nozzle energizing pulses. Registers in the Print Head Interface allow the accurate specification of the pulse duration between 0 and 6 ms, with a typical duration of 2 ms to 3 ms.

A parallel interface 125 connects the ICP to individual static electrical signals. The CPU is able to control each of these connections as memory mapped I/O via a low speed bus.

The following is a table of connections to the parallel interface:

    ______________________________________                                         Connection          Direction                                                                               Pins                                              ______________________________________                                         Paper transport stepper motor                                                                      Output   4                                                 Capping solenoid    Output   1                                                 Copy LED            Output   1                                                 Photo button        Input    1                                                 Copy button         Input    1                                                 Total                        8                                                 ______________________________________                                    

A serial interface is also included to allow authentication of the refill station. This is included to ensure that the cameras are only refilled with paper and ink at authorized refill stations, thus preventing inferior quality refill industry from occurring. The camera must authenticate the refill station, rather than the other way around. The secure protocol is communicated to the refill station via a serial data connection. Contact can be made to four gold plated spots on the ICP/printhead TAB by the refill station as the new ink is injected into the printhead.

Seven high current drive transistors eg. 227 are required. Four are for the four phases of the main stepper motor two are for the guillotine motor, and the remaining transistor is to drive the capping solenoid. These transistors are allocated 20,000 square microns (600,000 F) each. As the transistors are driving highly inductive loads, they must either be turned off slowly, or be provided with a high level of back EMF protection. If adequate back EMF protection cannot be provided using the chip process chosen, then external discrete transistors should be used. The transistors are never driven at the same time as the image sensor is used. This is to avoid voltage fluctuations and hot spots affecting the image quality. Further, the transistors are located as far away from the sensor as possible.

A standard JTAG (Joint Test Action Group) interface 228 is included in the ICP for testing purposes and for interrogation by the refill station. Due to the complexity of the chip, a variety of testing techniques are required, including BIST (Built In Self Test) and functional block isolation. An overhead of 10% in chip area is assumed for chip testing circuitry for the random logic portions. The overhead for the large arrays (the image sensor and the DRAM) is smaller.

The JTAG interface is also used for authentication of the refill station. This is included to ensure that the cameras are only refilled with quality paper and ink at a properly constructed refill station, thus preventing inferior quality refills from occurring. The camera must authenticate the refill station, rather than vice versa. The secure protocol is communicated to the refill station during the automated test procedure. Contact is made to four gold plated spots on the ICP/printhead TAB by the refill station as the new ink is injected into the printhead.

FIG. 16 illustrates rear view of the next step in the construction process whilst FIG. 17 illustrates a front camera view.

Turning now to FIG. 16, the assembly of the camera system proceeds via first assembling the ink supply mechanism 40. The flex PCB is interconnected with batteries only one of which is shown at 84, which are inserted in the middle portion of a print roll 85 which is wrapped around a plastic former 86. An end cap 89 is provided at the other end of the print roll 85 so as to fasten the print roll and batteries firmly to the ink supply mechanism.

The solenoid coil is interconnected (not shown) to interconnects 97, 98 (FIG. 8) which include leaf spring ends for interconnection with electrical contacts on the Flex PCB so as to provide for electrical control of the solenoid.

Turning now to FIGS. 17-19 the next step in the construction process is the insertion of the relevant gear chains into the side of the camera chassis. FIG. 17 illustrates a front camera view, FIG. 18 illustrates a back side view and FIG. 19 also illustrates a back side view. The first gear chain comprising gear wheels 22, 23 are utilised for driving the guillotine blade with the gear wheel 23 engaging the gear wheel 65 of FIG. 8. The second gear chain comprising gear wheels 24, 25 and 26 engage one end of the print roller 61 of FIG. 8. As best indicated in FIG. 18, the gear wheels mate with corresponding buttons on the surface of the chassis with the gear wheel 26 being snap fitted into corresponding mating hole 27.

Next, as illustrated in FIG. 20, the assembled platen unit is then inserted between the print roll 85 and aluminium cutting blade 43.

Turning now to FIG. 21, by way of illumination, there is illustrated the electrically interactive components of the camera system. As noted previously, the components are based around a Flex PCB board and include a TAB film 58 which interconnects the printhead 102 with the image sensor and processing chip 51. Power is supplied by two AA type batteries 83, 84 and a paper drive stepper motor 16 is provided in addition to a rotary guillotine motor 17.

An optical element 31 is provided for snapping into a top portion of the chassis 12. The optical element 31 includes portions defining an optical view finder 32, 33 which are slotted into mating portions 35, 36 in view finder channel 37. Also provided in the optical element 31 is a lensing system 38 for magnification of the prints left number in addition to an optical pipe element 39 for piping light from the LED 5 for external display.

Turning next to FIG. 22, the assembled unit 90 is then inserted into a front outer case 91 which includes button 4 for activation of printouts.

Turning now to FIG. 23, next, the unit 92 is provided with a snap-on back cover 93 which includes a slot 6 and copy print button 7. A wrapper label containing instructions and advertising (not shown) is then wrapped around the outer surface of the camera system and pinch clamped to the cover by means of clamp strip 96 which can comprise a flexible plastic or rubber strip.

Subsequently, the preferred embodiment is ready for use as a one time use camera system that provides for instant output images on demand. It will be evident that the preferred embodiment further provides for a refillable camera system. A used camera can be collected and its outer plastic cases removed and recycled. A new paper roll and batteries can be added and the ink cartridge refilled. A series of automatic test routines can then be carried out to ensure that the printer is properly operational. Further, in order to ensure only authorised refills are conducted so as to enhance quality, routines in the on-chip program ROM can be executed such that the camera authenticates the refilling station using a secure protocol. Upon authentication, the camera can reset an internal paper count and an external case can be fitted on the camera system with a new outer label. Subsequent packing and shipping can then take place.

It will be further readily evident to those skilled in the art that the program ROM can be modified so as to allow for a variety of digital processing routines. In addition to the digitally enhanced photographs optimised for mainstream consumer preferences, various other models can readily be provided through mere re-programming of the program ROM For example, a sepia classic old fashion style output can be provided through a remapping of the color mapping function. A further alternative is to provide for black and white outputs again through a suitable color remapping algorithm. Minimumless color can also be provided to add a touch of color to black and white prints to produce the effect that was traditionally used to colorize black and white photos. Further, passport photo output can be provided through suitable address remappings within the address generators. Further, edge filters can be utilised as is known in the field of image processing to produce sketched art styles. Further, classic wedding borders and designs can be placed around an output image in addition to the provision of relevant clip arts. For example, a wedding style camera might be provided. Further, a panoramic mode can be provided so as to output the well known panoramic format of images. Further, a postcard style output can be provided through the printing of postcards including postage on the back of a print roll surface. Further, clip arts can be provided for special events such as Halloween, Christmas etc. Further, kaleidoscopic effects can be provided through address remappings and wild color effects can be provided through remapping of the color lookup table. Many other forms of special event cameras can be provided for example, cameras dedicated to the Olympics, movie tie-ins, advertising and other special events.

The operational mode of the camera can be programmed so that upon the depressing of the take photo a first image is sampled by the sensor array to determine irrelevant parameters. Next a second image is again captured which is utilised for the output. The captured image is then manipulated in accordance with any special requirements before being initially output on the paper roll. The LED light is then activated for a predetermined time during which the DRAM is refreshed so as to retain the image. If the print copy button is depressed during this predetermined time interval, a further copy of the photo is output. After the predetermined time interval where no use of the camera has occurred, the onboard CPU shuts down all power to the camera system until such time as the take button is again activated. In this way, substantial power savings can be realized.

Ink Jet Technologies

The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable.

The most significant problem with thermal ink jet is power consumption. This is approximately 100 times that required for high speed, and stems from the energy-inefficient means of drop ejection. This involves the rapid boiling of water to produce a vapor bubble which expels the ink. Water has a very high heat capacity, and must be superheated in thermal ink jet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out.

The most significant problem with piezoelectric ink jet is size and cost. Piezoelectric crystals have a very small deflection at reasonable drive voltages, and therefore require a large area for each nozzle. Also, each piezoelectric actuator must be connected to its drive circuit on a separate substrate. This is not a significant problem at the current limit of around 300 nozzles per print head, but is a major impediment to the fabrication of page)width print heads with 19,200 nozzles.

Ideally, the ink jet technologies used meet the stringent requirements of in-camera digital color printing and other high quality, high speed, low cost printing applications. To meet the requirements of digital photography, new ink jet technologies have been created. The target features include:

low power (less than 10 Watts)

high resolution capability (1,600 dpi or more)

photographic quality output

low manufacturing cost

small size (pagewidth times minimum cross section)

high speed (<2 seconds per page).

All of these features can be met or exceeded by the ink jet systems described below with differing levels of difficulty. Forty-five different ink jet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the list under the heading Cross References to Related Applications.

The ink jet designs shown here are suitable for a wide range of digital printing systems, from battery powered one-time use digital cameras, through to desktop and network printers, and through to commercial printing systems

For ease of manufacture using standard process equipment, the print head is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic application, the print head is 100 mm long, with a width which depends upon the ink jet type. The smallest print head designed is covered in U.S. patent application No. 09/112,764, which is 0.35 mm wide, giving a chip area of 35 square mm. The print heads each contain 19,200 nozzles plus data and control circuitry.

Ink is supplied to the back of the print head by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The print head is connected to the camera circuitry by tape automated bonding.

Tables of Drop-on-Demand Ink Jets

The present invention is useful in the field of digital printing, in particular, ink jet printing. A number of patent applications in this field were filed simultaneously and incorporated by cross reference.

Eleven important characteristics of the fundamental operation of individual ink jet nozzles have been identified. These characteristics are largely orthogonal, and so can be elucidated as an eleven dimensional matrix. Most of the eleven axes of this matrix include entries developed by the present assignee.

The following tables form the axes of an eleven dimensional table of ink jet types.

Actuator mechanism (18 types)

Basic operation mode (7 types)

Auxiliary mechanism (8 types)

Actuator amplification or modification method (17 types)

Actuator motion (19 types)

Nozzle refill method (4 types)

Method of restricting back-flow through inlet (10 types)

Nozzle clearing method (9 types)

Nozzle plate construction (9 types)

Drop ejection direction (5 types)

Ink type (7 types)

The complete eleven dimensional table represented by these axes contains 36.9 billion possible configurations of ink jet nozzle. While not all of the possible combinations result in a viable ink jet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain ink jet types have been investigated in detail. Forty-five such inkjet types were filed simultaneously to the present application.

Other ink jet configurations can readily be derived from these forty-five examples by substituting alternative configurations along one or more of the 11 axes. Most of the forty-five examples can be made into ink jet print heads with characteristics superior to any currently available ink jet technology.

Where there are prior art examples known to the inventor, one or more of these examples are listed in the examples column of the tables below. The simultaneously filed patent applications by the present applicant are listed by USSN numbers. In some cases, a print technology may be listed more than once in a table, where it shares characteristics with more than one entry.

Suitable applications for the ink jet technologies include: Home printers, Office network printers, Short run digital printers, Commercial print systems, Fabric printers, Pocket printers, Internet WWW printers, Video printers, Medical imaging, Wide format printers, Notebook PC printers, Fax machines, Industrial printing systems, Photocopiers, Photographic minilabs etc.

The information associated with the aforementioned 11 dimensional matrix are set out in the following tables.

    __________________________________________________________________________             Description                                                                               Advantages Disadvantages                                                                             Examples                              __________________________________________________________________________     ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS)                        Thermal An electrothermal                                                                         Large force                                                                               High power Canon Bubblejet 1979                  bubble  heater heats the ink                                                                      generated  Ink carrier limited                                                                       Endo et al GB patent                          to above boiling                                                                          Simple     to water   2,007,162                                     point, transferring                                                                       construction                                                                              Low efficiency                                                                            Xerox heater-in-pit                           significant heat to                                                                       No moving  High temperatures                                                                         1990 Hawkins et al                            the aqueous ink. A                                                                        parts      required   USP 4,899,181                                 bubble nucleates                                                                          Fast operation                                                                            High mechanical                                                                           Hewlett-Packard TIJ                           and quickly forms,                                                                        Small chip area                                                                           stress     1982 Vaught et al USP                         expelling the ink.                                                                        required for                                                                              Unusual materials                                                                         4,490,728                                     The efficiency of the                                                                     actuator   required                                                 process is low, with  Large drive                                              typically less than   transistors                                              0.05% of the          Cavitation causes                                        electrical energy     actuator failure                                         being transformed     Kogation reduces                                         into kinetic energy   bubble formation                                         of the drop.          Large print heads                                                              are difficult to                                                               fabricate                                        Piezo-  A piezoelectric                                                                           Low power  Very large area                                                                           Kyser et al USP                       electric                                                                               crystal such as lead                                                                      consumption                                                                               required for                                                                              3,946,398                                     lanthanum zirconate                                                                       Many ink types                                                                            actuator   Zoltan USP 3,683,212                          (PZT) is electrically                                                                     can be used                                                                               Difficult to                                                                              1973 Stemme USP                               activated, and either                                                                     Fast operation                                                                            integrate with                                                                            3,747,120                                     expands, shears, or                                                                       High efficiency                                                                           electronics                                                                               Epson Stylus                                  bends to apply        High voltage drive                                                                        Tektronix                                     pressure to the ink,  transistors                                                                               USSN 09/112,803                               ejecting drops.       required                                                                       Full pagewidth                                                                 print heads                                                                    impractical due to                                                             actuator size                                                                  Requires electrical                                                            poling in high                                                                 field strengths                                                                during                                                                         manufacture                                      Electro-                                                                               An electric field is                                                                      Low power  Low maximum                                                                               Seiko Epson, Usui et all              strictive                                                                              used to activate                                                                          consumption                                                                               strain (approx.                                                                           JP 253401/96                                  electrostriction in                                                                       Many ink types                                                                            0.01%)     USSN 09/112,803                               relaxor materials                                                                         can be used                                                                               Large area                                               such as lead                                                                              Low thermal                                                                               required for                                             lanthanum zirconate                                                                       expansion  actuator due to                                          titanate (PLZT) or                                                                        Electric field                                                                            low strain                                               lead magnesium                                                                            strength   Response speed is                                        niobate (PMN).                                                                            required   marginal (˜10 μs)                                          (approx. 3.5                                                                              High voltage drive                                                  V/μm) can be                                                                           transistors                                                         generated  required                                                            without    Full pagewidth                                                      difficulty print heads                                                         Does not   impractical due to                                                  require    actuator size                                                       electrical poling                                           Ferro-  An electric field is                                                                      Low power  Difficult to                                                                              USSN 09/112,803                       electric                                                                               used to induce a                                                                          consumption                                                                               integrate with                                           phase transition                                                                          Many ink types                                                                            electronics                                              between the                                                                               can be used                                                                               Unusual materials                                        antiferroelectric                                                                         Fast operation                                                                            such as PLZSnT                                           (AFE) and  (<1 μs) are required                                             ferroelectric (FE)                                                                        Relatively high                                                                           Actuators require                                        phase Perovskite                                                                          longitudinal                                                                              a large area                                             materials such as tin                                                                     strain                                                              modified lead                                                                             High efficiency                                                     lanthanum zirconate                                                                       Electric field                                                      titanate (PLZSnT)                                                                         strength of                                                         exhibit large strains                                                                     around 3 V/μm                                                    of up to 1%                                                                               can be readily                                                      associated with the                                                                       provided                                                            AFE to FE phase                                                                transition.                                                            Electro-                                                                               Conductive plates                                                                         Low power  Difficult to                                                                              USSN 09/112,787;                      static  are separated by a                                                                        consumption                                                                               operate    09/112,803                            plates  compressible or                                                                           Many ink types                                                                            electrostatic                                            fluid dielectric                                                                          can be used                                                                               devices in an                                            (usually air). Upon                                                                       Fast operation                                                                            aqueous                                                  application of a      environment                                              voltage, the plates   The electrostatic                                        attract each other    actuator will                                            and displace ink,     normally need to                                         causing drop          be separated from                                        ejection. The         the ink                                                  conductive plates     Very large area                                          may be in a comb or   required to                                              honeycomb             achieve high                                             structure, or stacked forces                                                   to increase the       High voltage drive                                       surface area and      transistors may be                                       therefore the force.  required                                                                       Full pagewidth                                                                 print heads are not                                                            competitive due to                                                             actuator size                                    Electro-                                                                               A strong electric                                                                         Low current                                                                               High voltage                                                                              1989 Saito et al, USP                 static pull                                                                            field is applied to                                                                       consumption                                                                               required   4,799,068                             on ink  the ink, whereupon                                                                        Low        May be damaged                                                                            1989 Miura et al, USP                         electrostatic                                                                             temperature                                                                               by sparks due to                                                                          4,810,954                                     attraction            air breakdown                                                                             Tone-jet                                      accelerates the ink   Required field                                           towards the print     strength increases                                       medium.               as the drop size                                                               decreases                                                                      High voltage drive                                                             transistors                                                                    required                                                                       Electrostatic field                                                            attracts dust                                    Permanent                                                                              An electromagnet                                                                          Low power  Complex    USSN 09/113,084;                      magnet  directly attracts a                                                                       consumption                                                                               fabrication                                                                               09/112,779                            electro-                                                                               permanent magnet,                                                                         Many ink types                                                                            Permanent                                        magnetic                                                                               displacing ink and                                                                        can be used                                                                               magnetic material                                        causing drop                                                                              Fast operation                                                                            such as                                                  ejection. Rare earth                                                                      High efficiency                                                                           Neodymium Iron                                           magnets with a field                                                                      Easy extension                                                                            Boron (NdFeB)                                            strength around 1                                                                         from single                                                                               required.                                                Tesla can be used.                                                                        nozzles to High local                                               Examples are:                                                                             pagewidth print                                                                           currents required                                        Samarium Cobalt                                                                           heads      Copper                                                   (SaCo) and            metalization                                             magnetic materials    should be used for                                       in the neodymium      long                                                     iron boron family     electromigration                                         (NdFeB,               lifetime and low                                         NdDyFeBNb,            resistivity                                              NdDyFeB, etc)         Pigmented inks                                                                 are usually                                                                    infeasible                                                                     Operating                                                                      temperature                                                                    limited to the                                                                 Curie temperature                                                              (around 540 K)                                   Soft    A solenoid induced                                                                        Low power  Complex    USSN 09/112,751;                      magnetic                                                                               a magnetic field in a                                                                     consumption                                                                               fabrication                                                                               09/113,097; 09/113,066;               core    soft magnetic core                                                                        Many ink types                                                                            Materials not                                                                             09/112,779; 09/113,061;               electro-                                                                               or yoke fabricated                                                                        can be used                                                                               usually present in                                                                        09/112,816; 09/112,772;               magnetic                                                                               from a ferrous                                                                            Fast operation                                                                            a CMOS fab such                                                                           09/112,815                                    material such as                                                                          High efficiency                                                                           as NiFe, CoNiFe,                                         electroplated iron                                                                        Easy extension                                                                            or CoFe are                                              alloys such as                                                                            from single                                                                               required                                                 CoNiFe [1], CoFe,                                                                         nozzles to High local                                               or NiFe alloys.                                                                           pagewidth print                                                                           currents required                                        Typically, the soft                                                                       heads      Copper                                                   magnetic material is  metalization                                             in two parts, which   should be used for                                       are normally held     long                                                     apart by a spring.    electromigration                                         When the solenoid     lifetime and low                                         is actuated, the two  resistivity                                              parts attract,        Electroplating is                                        displacing the ink.   required                                                                       High saturation                                                                flux density is                                                                required (2.0-2.1                                                              T is achievable                                                                with CoNiFe [1])                                 Lorenz  The Lorenz force                                                                          Low power  Force acts as a                                                                           USSN 09/113,099;                      force   acting on a current                                                                       consumption                                                                               twisting motion                                                                           09/113,077; 09/112,818;                       carrying wire in a                                                                        Many ink types                                                                            Typically, only a                                                                         09/112,819                                    magnetic field is                                                                         can be used                                                                               quarter of the                                           utilized.  Fast operation                                                                            solenoid length                                          This allows the                                                                           High efficiency                                                                           provides force in a                                      magnetic field to be                                                                      Easy extension                                                                            useful direction                                         supplied eternally                                                                        from single                                                                               High local                                               to the print head, for                                                                    nozzles to currents required                                        example with rare                                                                         pagewidth print                                                                           Copper                                                   earth permanent                                                                           heads      metalization                                             magnets.              should be used for                                       Only the current      long                                                     carrying wire need    electromigration                                         be fabricated on the  lifetime and low                                         print-head,           resistivity                                              simplifying           Pigmented inks                                           materials             are usually                                              requirements.         infeasible                                       Magneto-                                                                               The actuator uses                                                                         Many ink types                                                                            Force acts as a                                                                           Fischenbeck, USP                      striction                                                                              the giant  can be used                                                                               twisting motion                                                                           4,032,929                                     magnetostrictive                                                                          Fast operation                                                                            Unusual materials                                                                         USSN 09/113,121                               effect of materials                                                                       Easy extension                                                                            such as Terfenol-                                        such as Terfenol-D                                                                        from single                                                                               D are required                                           (an alloy of terbium,                                                                     nozzles to High local                                               dysprosium and iron                                                                       pagewidth print                                                                           currents required                                        developed at the                                                                          heads      Copper                                                   Naval Ordnance                                                                            High force is                                                                             metalization                                             Laboratory, hence                                                                         available  should be used for                                       Ter-Fe-NOL). For      long                                                     best efficiency, the  electromigration                                         actuator should be    lifetime and low                                         pre-stressed to       resistivity                                              approx. 8 MPa.        Pre-stressing may                                                              be required                                      Surface Ink under positive                                                                        Low power  Requires   Silverbrook, EP 0771                  tension pressure is held in a                                                                     consumption                                                                               supplementary                                                                             658 A2 and related                    reduction                                                                              nozzle by surface                                                                         Simple     force to effect                                                                           patent applications                           tension. The surface                                                                      construction                                                                              drop separation                                          tension of the ink is                                                                     No unusual Requires special                                         reduced below the                                                                         materials  ink surfactants                                          bubble threshold,                                                                         required in                                                                               Speed may be                                             causing the ink to                                                                        fabrication                                                                               limited by                                               egress from the                                                                           High efficiency                                                                           surfactant                                               nozzle.    Easy extension                                                                            properties                                                          from single                                                                    nozzles to                                                                     pagewidth print                                                                heads                                                       Viscosity                                                                              The ink viscosity is                                                                      Simple     Requires   Silverbrook, EP 0771                  reduction                                                                              locally reduced to                                                                        construction                                                                              supplementary                                                                             658 A2 and related                            select which drops                                                                        No unusual force to effect                                                                           patent applications                           are to be ejected. A                                                                      materials  drop separation                                          viscosity reduction                                                                       required in                                                                               Requires special                                         can be achieved                                                                           fabrication                                                                               ink viscosity                                            electrothermally                                                                          Easy extension                                                                            properties                                               with most inks, but                                                                       from single                                                                               High speed is                                            special inks can be                                                                       nozzles to difficult to achieve                                     engineered for a                                                                          pagewidth print                                                                           Requires                                                 100: 1 viscosity                                                                          heads      oscillating ink                                          reduction.            pressure                                                                       A high                                                                         temperature                                                                    difference                                                                     (typically 80                                                                  degrees) is                                                                    required                                         Acoustic                                                                               An acoustic wave is                                                                       Can operate                                                                               Complex drive                                                                             1993 Hadimioglu et al,                        generated and                                                                             without a nozzle                                                                          circuitry  EUP 550, 192                                  focused upon the                                                                          plate      Complex    1993 Elrod et al, EUP                         drop ejection region. fabrication                                                                               572,220                                                             Low efficiency                                                                 Poor control of                                                                drop position                                                                  Poor control of                                                                drop volume                                      Thermo- An actuator which                                                                         Low power  Efficient aqueous                                                                         USSN 09/112,802;                      elastic relies upon                                                                               consumption                                                                               operation requires                                                                        09/112,778; 09/112,815;               bend    differential thermal                                                                      Many ink types                                                                            a thermal insulator                                                                       09/113,096; 09/113,068;               actuator                                                                               expansion upon                                                                            can be used                                                                               on the hot side                                                                           09/113,095; 09/112,808;                       Joule heating is                                                                          Simple planar                                                                             Corrosion  09/112,809; 09/112,780;                       used.      fabrication                                                                               prevention can be                                                                         09/113,083; 09/112,793;                                  Small chip area                                                                           difficult  09/112,794; 09/113,128;                                  required for                                                                              Pigmented inks                                                                            09/113,127; 09/112,756;                                  each actuator                                                                             may be infeasible                                                                         09/112,755; 09/112,754;                                  Fast operation                                                                            as pigment 09/112,811; 09/112,812;                                  High efficiency                                                                           particles may jam                                                                         09/112,813; 09/112,814;                                  CMOS       The bend aviator                                                                          09/112,764; 09/112,765;                                  compatible            09/112,767; 09/112,768                                   voltages and                                                                   currents                                                                       Standard                                                                       MEMS                                                                           processes can                                                                  be used                                                                        Easy extension                                                                 from single                                                                    nozzles to                                                                     pagewidth print                                                                heads                                                       High CTE                                                                               A material with a                                                                         High force can                                                                            Requires special                                                                          USSN 09/112,778;                      thermo- very high coefficient                                                                     be generated                                                                              material (e.g.                                                                            09/112,815; 09/113,096;               elastic of thermal Three methods                                                                             PTFE)      09/113,095; 09/112,808;               actuator                                                                               expansion (CFE)                                                                           of PTFE    Requires a PTFE                                                                           09/112,809; 09/112,780;                       such as    deposition are                                                                            deposition 09/113,083; 09/112,793;                       polytetrafluoroethyl                                                                      under      process, which is                                                                         09/112,794; 091113,128;                       ene is used.                                                                              development:                                                                              not yet standard in                                                                       09/113,127; 09/112,756;                       As high CTE                                                                               chemical vapor                                                                            ULSI fabs  09/112,807; 09/112,806;                       materials are usually                                                                     deposition PTFE deposition                                                                           09/112,820                                    nonconductive, a                                                                          (CVD), spin                                                                               cannot be                                                heater fabricated                                                                         coating, and                                                                              followed with                                            from a conductive                                                                         evaporation                                                                               high temperature                                         material is                                                                               PTFE is a  (above 350° C.)                                   incorporated. A 50                                                                        candidate for                                                                             processing                                               μm long PTFE bend                                                                      low dielectric                                                                            Pigmented inks                                           actuator with                                                                             constant   may be infeasible,                                       polysilicon heater                                                                        insulation in                                                                             as pigment                                               and 15 mW power                                                                           ULSI       particles may jam                                        input can provide                                                                         Very low power                                                                            the bend actuator                                        180 μN force and 10                                                                    consumption                                                         μm deflection.                                                                         Many ink types                                                      Actuator motions                                                                          can be used                                                         include:   Simple planar                                                       Bend       fabrication                                                         Push       Small chip area                                                     Buckle     required for                                                                   each actuator                                                       Rotate     Fast operation                                                                 High efficiency                                                                CMOS                                                                           compatible                                                                     voltages and                                                                   currents                                                                       Easy extension                                                                 from single                                                                    nozzles to                                                                     pagewidth print                                                                heads                                                       Conduct-                                                                               A polymer with a                                                                          High force can                                                                            Requires special                                                                          USSN 09/113,083                       ive     high coefficient of                                                                       be generated                                                                              materials                                        polymer thermal expansion                                                                         Very low power                                                                            development                                      thermo- (such as PTFE) is                                                                         consumption                                                                               (High CTE                                        elastic doped with Many ink types                                                                            conductive                                       actuator                                                                               conducting can be used                                                                               polymer)                                                 substances to                                                                             Simple planar                                                                             Requires a PTFE                                          increase its                                                                              fabrication                                                                               deposition                                               conductivity to                                                                           Small chip area                                                                           process, which is                                        about 3 orders of                                                                         required for                                                                              not yet standard in                                      magnitude below                                                                           each actuator                                                                             ULSI fabs                                                that of copper. The                                                                       Fast operation                                                                            PTFE deposition                                          conducting polymer                                                                        High efficiency                                                                           cannot be                                                expands when                                                                              CMOS       followed with                                            resistively heated.                                                                       compatible high temperature                                         Examples of                                                                               voltages and                                                                              (above 350° C.)                                   conducting dopants                                                                        currents   processing                                               include:   Easy extension                                                                            Evaporation and                                          Carbon nanotubes                                                                          from single                                                                               CVD deposition                                           Metal fibers                                                                              nozzles to techniques cannot                                        Conductive pagewidth print                                                                           be used                                                  polymers such as                                                                          heads      Pigmented inks                                           doped                 may be infeasible,                                       polythiophene         as pigment                                               Carbon granules       particles may jam                                                              the bend actuator                                Shape   A shape memory                                                                            High force is                                                                             Fatigue limits                                                                            USSN 09/113,122                       memory  alloy such as TiNi                                                                        available  maximum number                                   alloy   (also known as                                                                            (stresses of                                                                              of cycles                                                Nitinol - Nickel                                                                          hundreds of                                                                               Low strain (1%) is                                       Titanium alloy                                                                            MPa)       required to extend                                       developed at the                                                                          Large strain is                                                                           fatigue resistance                                       Naval Ordnance                                                                            available (more                                                                           Cycle rate limited                                       Laboratory) is                                                                            than 3%)   by heat removal                                          thermally switched                                                                        High corrosion                                                                            Requires unusual                                         between its weak                                                                          resistance materials (TiNi)                                         martensitic state and                                                                     Simple     The latent heat of                                       its high stiffness                                                                        construction                                                                              transformation                                           austenic state. The                                                                       Easy extension                                                                            must be provided                                         shape of the actuator                                                                     from single                                                                               High current                                             in its martensitic                                                                        nozzles to operation                                                state is deformed                                                                         pagewidth print                                                                           Requires pre-                                            relative to the                                                                           heads      stressing to distort                                     austenic shape. The                                                                       Low voltage                                                                               the martensitic                                          shape change causes                                                                       operation  state                                                    ejection of a drop.                                                    Linear  Linear magnetic                                                                           Linear Magnetic                                                                           Requires unusual                                                                          USSN 09/113,061                       Magnetic                                                                               actuators include the                                                                     actuators can be                                                                          semiconductor                                    Actuator                                                                               Linear Induction                                                                          constricted with                                                                          materials such as                                        Actuator (LIA),                                                                           high thrust, long                                                                         soft magnetic                                            Linear Permanent                                                                          travel, and high                                                                          alloys (e.g.                                             Magnet     efficiency using                                                                          CoNiFe)                                                  Synchronous                                                                               planar     Some varieties                                           Actuator (LPMSA),                                                                         semiconductor                                                                             also require                                             Linear Reluctance                                                                         fabrication                                                                               permanent                                                Synchronous                                                                               techniques magnetic                                                 Actuator (LRSA),                                                                          Long actuator                                                                             materials such as                                        Linear Switched                                                                           travel is  Neodymium iron                                           Reluctance Actuator                                                                       available  boron (NdFeB)                                            (LSRA), and the                                                                           Medium force is                                                                           Requires complex                                         Linear Stepper                                                                            available  multi-phase drive                                        Actuator (LSA).                                                                           Low voltage                                                                               circuitry                                                           operation  High current                                                                   operation                                        BASIC OPERATION MODE                                                           Actuator                                                                               This is the simplest                                                                      Simple     Drop repetition                                                                           Thermal ink jet                       directly                                                                               mode of operation:                                                                        operation  rate is usually                                                                           Piezoelectric ink jet                 pushes ink                                                                             the actuator directly                                                                     No external                                                                               limited to around                                                                         USSN 09/112,751;                              supplies sufficient                                                                       fields required                                                                           10 kHz.    09/112,787; 09/112,802;                       kinetic energy to                                                                         Satellite drops                                                                           However, this is                                                                          09/112,803; 09/113,097;                       expel the drop. The                                                                       can be avoided                                                                            not fundamental                                                                           09/113,099; 09/113,084;                       drop must have a                                                                          if drop velocity                                                                          to the method,                                                                            09/112,778; 09/113,077;                       sufficient velocity to                                                                    is less than 4                                                                            but is related to                                                                         09/113,061; 09/112,816;                       overcome the                                                                              m/s        the refill method                                                                         09/112,819; 09/113,095;                       surface tension.                                                                          Can be efficient,                                                                         normally used                                                                             09/112,809; 09/112,780;                                  depending upon                                                                            All of the drop                                                                           09/113,083; 09/113,121;                                  the actuator                                                                              kinetic energy                                                                            09/113,122; 09/112,793;                                  used       must be provided                                                                          09/112,794; 09/113,128;                                             by the actuator                                                                           09/113,127; 09/112,756;                                             Satellite drops                                                                           09/112,755; 09/112,754;                                             usually form if                                                                           09/112,811; 09/112,812;                                             drop velocity is                                                                          09/112,813; 09/112,814;                                             greater than 4.5                                                                          09/112,764; 09/112,765;                                             m/s        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820                            Proximity                                                                              The drops to be                                                                           Very simple                                                                               Requires close                                                                            Silverbrook, EP 0771                          printed are selected                                                                      print head proximity  658 A2 and related                            by some manner                                                                            fabrication can                                                                           between the print                                                                         patent applications                           (e.g. thermally                                                                           be used    head and the -                                                                            induced surface The drop print                                                 media or                                      tension reduction of                                                                      selection means                                                                           transfer roller                                          pressurized ink).                                                                         does not need to                                                                          May require -                                                                             Selected drops are provide                                                     the print heads                               separated from the                                                                        energy required                                                                           printing alternate                                       ink in the nozzle by                                                                      to separate the                                                                           rows of the                                              contact with the                                                                          drop from image                                                     print medium or a                                                                         nozzle     Monolithic color                                         transfer roller.      print heads are                                                                difficult                                        Electro-                                                                               The drops to be                                                                           Very simple                                                                               Requires very                                                                             Silverbrook, EP 0771                  static pull                                                                            printed are selected                                                                      print head high electrostatic                                                                        658 A2 and related                    on ink  by some manner                                                                            fabrication can                                                                           field      patent applications                           (e.g. thermally                                                                           be used    Electrostatic field                                                                       Tone-Jet                                      induced surface                                                                           The drop   for small nozzle                                         tension reduction of                                                                      selection means                                                                           sizes is above air                                       pressurized ink).                                                                         does not need to                                                                          breakdown                                                Selected drops are                                                                        provide the                                                                               Electrostatic field                                      separated from the                                                                        energy required                                                                           may attract dust                                         ink in the nozzle by                                                                      to separate the                                                     a strong electric                                                                         drop from the                                                       field.     nozzle                                                      Magnetic                                                                               The drops to be                                                                           Very simple                                                                               Requires   Silverbrook, EP 0771                  pull on ink                                                                            printed are selected                                                                      print head magnetic ink                                                                              658 A2 and related                            by some manner                                                                            fabrication can                                                                           Ink colors other                                                                          patent applications                           (e.g. thermally                                                                           be used    than black are                                           induced surface                                                                           The drop   difficult                                                tension reduction of                                                                      selection means                                                                           Requires very                                            pressurized ink).                                                                         does not need to                                                                          high magnetic                                            Selected drops are                                                                        provide the                                                                               fields                                                   separated from the                                                                        energy required                                                     ink in the nozzle by                                                                      to separate the                                                     a strong magnetic                                                                         drop from the                                                       field acting on the                                                                       nozzle                                                              magnetic ink.                                                          Shutter The actuator moves                                                                        High speed Moving parts are                                                                          USSN 09/112,818;                              a shutter to block                                                                        (>50 kHz)  required   09/112,815; 09/112,808                        ink flow to the                                                                           operation can be                                                                          Requires ink                                             nozzle. The ink                                                                           achieved due to                                                                           pressure                                                 pressure is pulsed at                                                                     reduced refill                                                                            modulator                                                a multiple of the                                                                         time       Friction and wear                                        drop ejection                                                                             Drop timing can                                                                           must be                                                  frequency. be very accurate                                                                          considered                                                          The actuator                                                                              Striction is                                                        energy can be                                                                             possible                                                            very low                                                    Shuttered                                                                              The actuator moves                                                                        Actuators with                                                                            Moving parts are                                                                          USSN 09/113,066;                      grill   a shutter to block                                                                        small travel can                                                                          required   09/112,772; 09/113,096;                       ink flow through a                                                                        be used    Requires ink                                                                              09/113,068                                    grill to the nozzle.                                                                      Actuators with                                                                            pressure                                                 The shutter                                                                               small force can                                                                           modulator                                                movement need                                                                             be used    Friction and wear                                        only be equal to the                                                                      High speed must be                                                  width of the grill                                                                        (>50 kHz)  considered                                               holes.     operation can be                                                                          Striction is                                                        achieved   possible                                         Pulsed  A pulsed magnetic                                                                         Extremely low                                                                             Requires an                                                                               USSN 09/112,779                       magnetic                                                                               field attracts an `ink                                                                    energy     external pulsed                                  pull on ink                                                                            pusher` at the drop                                                                       operation is                                                                              magnetic field                                   pusher  ejection frequency.                                                                       possible   Requires special                                         An actuator controls                                                                      No heat    materials for both                                       a catch, which                                                                            dissipation                                                                               the actuator and                                         prevents the ink                                                                          problems   the ink pushier                                          pusher from moving    Complex                                                  when a drop is not    construction                                             to be ejected.                                                         AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES)                                   None    The actuator directly                                                                     Simplicity of                                                                             Drop ejection                                                                             Most ink jets, including                      fires the ink drop,                                                                       construction                                                                              energy must be                                                                            piezoelectric and thermal                     and there is no                                                                           Simplicity of                                                                             Supplied by                                                                               bubble.                                       external field or                                                                         operation  individual nozzle                                                                         USSN 09/112,751;                              other mechanism                                                                           Small physical                                                                            actuator   09/112,787; 09/112,802;                       required.  size                  09/112,803; 09/113,097;                                                        09/113,084; 09/113,078;                                                        09/113,077; 09/113,061;                                                        09/112,816; 09/113,095;                                                        09/112,809; 09/112,780;                                                        09/113,083; 09/113,121;                                                        09/113,122; 09/112,793;                                                        09/112,794; 09/113,128;                                                        09/113,127; 09/112,756;                                                        09/112,755; 09/112,754;                                                        09/112,811; 09/112,812;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820                            Oscillating                                                                            The ink pressure                                                                          Oscillating ink                                                                           Requires external                                                                         Silverbrook, EP 0771                  ink     oscillates, providing                                                                     pressure can                                                                              ink pressure                                                                              658 A2 and related                    pressure                                                                               much of the drop                                                                          provide a refill                                                                          oscillator patent applications                   (including                                                                             ejection energy. The                                                                      pulse, allowing                                                                           . Ink pressure                                                                            USSN 09/113,066;                      acoustic                                                                               actuator selects                                                                          higher operating                                                                          phase and  09/112,818; 09/112,772;               stimul- which drops are to                                                                        speed      amplitude must                                                                            09/112,815; 09/113,096;               ation)  be fired by                                                                               The actuators                                                                             be carefully                                                                              09/113,068; 09/112,808                        selectively blocking                                                                      may operate                                                                               controlled                                               or enabling nozzles.                                                                      with much  Acoustic                                                 The ink pressure                                                                          lower energy                                                                              reflections in the                                       oscillation may be                                                                        Acoustic lenses                                                                           ink chamber                                              achieved by                                                                               can be used to                                                                            must be designed                                         vibrating the print                                                                       focus the sound                                                                           for                                                      head, or preferably                                                                       on the nozzles                                                      by an actuator in the                                                          ink supply.                                                            Media   The print head is                                                                         Low power  Precision  Silverbrook, EP 0771                  proximity                                                                              placed in close                                                                           High accuracy                                                                             assembly   658 A2 and related                            proximity to the                                                                          Simple print                                                                              required   patent applications                           print medium.                                                                             head       Paper fibers may                                         Selected drops                                                                            construction                                                                              cause problems                                           protrude from the     Cannot print on                                          print head further    rough substrates                                         than unselected                                                                drops, and contact                                                             the print medium.                                                              The drop soaks into                                                            the medium fast                                                                enough to cause                                                                drop separation.                                                       Transfer                                                                               Drops are printed to                                                                      High accuracy                                                                             Bulky      Silverbrook, EP 0771                  roller  a transfer roller                                                                         Wide range of                                                                             Expensive  658 A2 and related                            instead of straight to                                                                    print substrates                                                                          Complex    patent applications                           the print medium. A                                                                       can be used                                                                               construction                                                                              Tektronix hot melt                            transfer roller can                                                                       Ink can be dried      piezoelectric ink jet                         also be used for                                                                          on the transfer       Any of USSN                                   proximity drop                                                                            roller                09/112,751; 09/112,787;                       separation.                      09/112,802; 09/112,803;                                                        09/113,097; 09/113,099;                                                        09/113,084; 09/113,066;                                                        09/112,778; 091112,779;                                                        09/113,077; 09/113,061;                                                        09/112,818; 09/112,816;                                                        09/112,772; 09/112,819;                                                        09/112,815; 09/113,096;                                                        091113,068; 09/113,095;                                                        09/112,808; 09/112,809;                                                        09/112,780; 09/113,083;                                                        09/113,121; 09/113,122;                                                        09/112,793; 09/112,794;                                                        09/113,128; 09/113,127;                                                        09/112,756; 09/112,755;                                                        09/112,754; 09/112,811;                                                        09/112,812; 09/112,813;                                                        09/112,814; 09/112,764;                                                        09/112,765; 09/112,767;                                                        09/112,768; 09/112,807;                                                        09/112,806; 09/112,820;                                                        09/112,821                            Electro-                                                                               An electric field is                                                                      Low power  Field strength                                                                            Silverbrook, EP 0771                  static  used to accelerate                                                                        Simple print                                                                              required for                                                                              658 A2 and related                            selected drops                                                                            head       separation of                                                                             patent applications                           towards the print                                                                         construction                                                                              small drops is                                                                            Tone-Jet                                      medium.               near or above air                                                              breakdown                                        Direct  A magnetic field is                                                                       Low power  Requires   Silverbrook, EP 0771                  magnetic                                                                               used to accelerate                                                                        Simple print                                                                              magnetic ink                                                                              658 A2 and related                    field   selected drops of                                                                         head       Requires strong                                                                           patent applications                           magnetic ink                                                                              construction                                                                              magnetic field                                           towards the print                                                              medium.                                                                Cross   The print head is                                                                         Does not   Requires external                                                                         USSN 09/113,099;                      magnetic                                                                               placed in a constant                                                                      require    magnet     09/112,819                            field   magnetic field. The                                                                       magnetic   Current densities                                        lorenz force in a                                                                         materials to be                                                                           may be high,                                             current carrying                                                                          integrated in the                                                                         resulting in                                             wire is used to move                                                                      print head electromigration                                         the actuator.                                                                             manufacturing                                                                             problems                                                            process                                                     Pulsed  A pulsed magnetic                                                                         Very low power                                                                            Complex print                                                                             USSN 09/112,779                       magnetic                                                                               field is used to                                                                          operation is                                                                              head construction                                field   cyclically attract a                                                                      possible   Magnetic                                                 paddle, which                                                                             Small print head                                                                          materials                                                pushes on the ink. A                                                                      size       required in print                                        Small actuator        head                                                     moves a catch,                                                                 which selectively                                                              prevents the paddle                                                            from moving.                                                           ACTUATOR AMPLIFICATION OR MODIFICATION METHOD                                  None    No actuator                                                                               Operational                                                                               Many actuator                                                                             Thermal Bubble Inkjet                         mechanical simplicity mechanisms USSN 09/112,751;                              amplification is      have       09/112,787; 09/113,099;                       used. The actuator    insufficient                                                                              09/113,084; 09/112,819;                       directly drives the   travel, or 09/113,121; 09/113,122                        drop ejection         insufficient                                             process.              force, to                                                                      efficiently drive                                                              the drop                                                                       ejection process                                 Differential                                                                           An actuator material                                                                      Provides greater                                                                          High stresses                                                                             Piezoelectric                         expansion                                                                              expands more on                                                                           travel in a                                                                               are involved                                                                              USSN 09/112,802;                      bend    one side than on the                                                                      reduced print                                                                             Care must be                                                                              09/112,778; 09/112,815;               actuator                                                                               other. The head area  taken that the                                                                            09/113,096; 09/113,068;                       expansion maybe       materials do not                                                                          09/113,095; 09/112,808;                       thermal,              delaminate 09/112,809; 09/112,780;                       piezoelectric,        Residual bend                                                                             09/113,083; 09/112,793;                       magnetostrictive, or  resulting from                                                                            09/113,128; 09/113,127;                       other mechanism.      high       09/112,756; 09/112,755;                       The bend actuator     temperature or                                                                            09/112,754; 09/112,811;                       converts a high       high stress                                                                               09/112,812; 09/112,813;                       force low travel      during     09/112,814; 09/112,764;                       actuator mechanism    formation  09/112,765; 09/112,767;                       to high travel, lower            09/112,768; 09/112,807;                       force mechanism.                 09/112,806; 09/112,820                Transient                                                                              A trilayer bend                                                                           Very good  High stresses                                                                             USSN 09/112,767;                      bend    actuator where the                                                                        temperature                                                                               are involved                                                                              09/112,768                            actuator                                                                               two outside layers                                                                        stability  Care must be                                             are identical. This                                                                       High speed, as a                                                                          taken that the                                           cancels bend due to                                                                       new drop can be                                                                           materials do not                                         ambient temperature                                                                       fired before heat                                                                         delaminate                                               and residual stress.                                                                      dissipates                                                          The actuator only                                                                         Cancels residual                                                    responds to transient                                                                     stress of                                                           heating of one side                                                                       formation                                                           or the other.                                                          Reverse The actuator loads a                                                                      Better coupling                                                                           Fabrication                                                                               USSN 09/113,097;                      spring  spring. When the                                                                          to the ink complexity 09/113,077                                    actuator is turned    High stress in                                           off, the spring       the spring                                               releases. This can                                                             reverse the                                                                    force/distance curve                                                           of the actuator to                                                             make it compatible                                                             with the force/time                                                            requirements of the                                                            drop ejection.                                                         Actuator                                                                               A series of thin                                                                          Increased travel                                                                          Increased  Some piezoelectric ink                stack   actuators are                                                                             Reduced drive                                                                             fabrication                                                                               jets                                          stacked. This can be                                                                      voltage    complexity USSN 09/112,803                               appropriate where     Increased                                                actuators require     possibility of                                           high electric field   short circuits                                           strength, such as     due to pinholes                                          electrostatic and                                                              piezoelectric                                                                  actuators.                                                             Multiple                                                                               Multiple smaller                                                                          Increases the                                                                             Actuator forces                                                                           USSN 09/113,061;                      actuators                                                                              actuators are used                                                                        force available                                                                           may not add                                                                               09/112,818; 09/113,096;                       simultaneously to                                                                         from an actuator                                                                          linearly,  09/113,095; 09/112,809;                       move the ink. Each                                                                        Multiple   reducing   09/112,794; 09/112,807;                       actuator need                                                                             actuators can be                                                                          efficiency 09/112,806                                    provide only a                                                                            Positioned to                                                       portion of the force                                                                      control ink flow                                                    required.  accurately                                                  Linear  A linear spring is                                                                        Matches low                                                                               Requires print                                                                            USSN 09/112,772                       Spring  used to transform a                                                                       travel actuator                                                                           head area for                                            motion with small                                                                         with higher                                                                               the spring                                               travel and high force                                                                     travel                                                              into a longer travel,                                                                     requirements                                                        lower force motion.                                                                       Non-contact                                                                    method of                                                                      motion                                                                         transformation                                              Coiled  A bend actuator is                                                                        Increases travel                                                                          Generally  USSN 09/112,815;                      actuator                                                                               coiled to provide                                                                         Reduces chip                                                                              restricted to                                                                             09/112,808; 09/112,811;                       greater travel in a                                                                       area       planar     09/112,812                                    reduced chip area.                                                                        Planar     implementation                                                      implementation                                                                            s due to extreme                                                    s are relatively                                                                          fabrication                                                         easy to    difficulty in                                                       fabricate. other                                                                          orientations.                                    Flexure A bend actuator has                                                                       Simple means                                                                              Care must be                                                                              USSN 09/112,779;                      bend    a small region near                                                                       of increasing                                                                             taken not to                                                                              09/113,068; 09/112,754                actuator                                                                               the fixture point,                                                                        travel of a bend                                                                          exceed the                                               which flexes much                                                                         actuator   elastic limit in                                         more readily than     the flexure area                                         the remainder of the  Stress                                                   actuator. The         distribution is                                          actuator flexing is   very uneven                                              effectively           Difficult to                                             converted from an     accurately                                               even coiling to an    model with                                               angular bend,         finite element                                           resulting in greater  analysis                                                 travel of the actuator                                                         tip.                                                                   Catch   The actuator                                                                              Very low   Complex    USSN 09/112,779                               controls a small                                                                          actuator energy                                                                           constriction                                             catch. The catch                                                                          Very small Requires                                                 either enables or                                                                         actuator size                                                                             external force                                           disables movement     Unsuitable for                                           of an ink pusher that pigmented inks                                           is controlled in a                                                             bulk manner.                                                           Gears   Gears can be used to                                                                      Low force, low                                                                            Moving pans                                                                               USSN 09/112,818                               increase travel at the                                                                    travel actuators                                                                          are required                                             expense of duration.                                                                      can be used                                                                               Several actuator                                         Circular gears, rack                                                                      Can be     cycles are                                               and pinion, ratchets,                                                                     fabricated using                                                                          required                                                 and other gearing                                                                         standard surface                                                                          More complex                                             methods can be                                                                            MEMS       drive electronics                                        used.      processes  Complex                                                                        construction                                                                   Friction,                                                                      friction, and                                                                  wear are                                                                       possible                                         Buckle  A buckle plate can                                                                        Very fast  Must stay  S. Hirata et al, "Ink-jet             plate   be used to change a                                                                       movement   within elastic                                                                            Head Using Diaphragm                          low actuator into a                                                                       achievable limits of the                                                                             Microactuator", Proc.                         fast motion. It can   materials for                                                                             IEEE MEMS, Feb. 1996,                         also convert a high   long device - life                                                                        pp 418-423.                                   force, low travel     High stresses                                                                             USSN 09/113,096;                              actuator into a high  involved   09/112,793                                    travel, medium force  Generally high                                           motion.               power                                                                          requirement                                      Tapered A tapered magnetic                                                                        Linearizes the                                                                            Complex    USSN 09/112,816                       magnetic                                                                               pole can increase                                                                         magnetic   construction                                     pole    travel at the expense                                                                     force/distance                                                      of force.  curve                                                       Lever   A lever and fulcrum                                                                       Matches low                                                                               High stress                                                                               USSN 09/112,755;                              is used to transform                                                                      travel actuator                                                                           around the 09/112,813; 09/112,814                        a motion with small                                                                       with higher                                                                               fulcrum                                                  travel and high force                                                                     travel                                                              into a motion with                                                                        requirements                                                        longer travel and                                                                         Fulcrum area                                                        lower force. The                                                                          has no linear                                                       lever can also                                                                            movement, and                                                       reverse the direction                                                                     can be used for                                                     of travel. a fluid seal                                                Rotary  The actuator is                                                                           High       Complex    USSN 09/112,794                       impeller                                                                               connected to a                                                                            mechanical construction                                             rotary impeller. A                                                                        advantage  Unsuitable for                                           small angular                                                                             The ratio of                                                                              pigmented inks                                           deflection of the                                                                         force to travel                                                     actuator results in a                                                                     of the actuator                                                     rotation of the                                                                           can be matched                                                      impeller vanes,                                                                           to the nozzle                                                       which push the ink                                                                        requirements by                                                     against stationary                                                                        varying the                                                         vanes and out of the                                                                      number of                                                           nozzle.    impeller vanes                                              Acoustic                                                                               A refractive or                                                                           No moving  Large area 1993 Hadimioglu et al,                lens    diffractive (e.g. zone                                                                    parts      required   EUP 550,192                                   plate) acoustic lens  Only relevant                                                                             1993 Elrod et al, EUP                         is used to            for acoustic ink                                                                          572,220                                       concentrate sound     jets                                                     waves.                                                                 Sharp   A sharp point is                                                                          Simple     Difficult to                                                                              Tone-jet                              conductive                                                                             used to concentrate                                                                       construction                                                                              fabricate using                                  point   an electrostatic field.                                                                              standard VLSI                                                                  processes for a                                                                surface ejecting                                                               ink-jet                                                                        Only relevant                                                                  for electrostatic                                                              ink jet                                          ACTUATOR MOTION                                                                Volume  The volume of the                                                                         Simple     High energy is                                                                            Hewlett-Packard Thermal               expansion                                                                              actuator changes,                                                                         construction in                                                                           typically  Inkjet                                        pushing the ink in                                                                        the case of                                                                               required to                                                                               Canon Bubblejet                               all directions.                                                                           thermal ink jet                                                                           achieve volume                                                                 expansion. This                                                                leads to thermal                                                               stress,                                                                        cavitation, and                                                                kogation in                                                                    thermal ink jet                                                                implementations                                  Linear  The actuator moves                                                                        Efficient  High fabrication                                                                          USSN 09/112,751;                      normal to                                                                              in a direction normal                                                                     coupling to ink                                                                           complexity may                                                                            09/112,787; 09/112,803;               chip    to the print head                                                                         drops ejected                                                                             be required to                                                                            09/113,084; 09/113,077,               surface surface. The nozzle                                                                       normal to the                                                                             achieve    09/112,816                                    is typically in the                                                                       surface    perpendicular                                            line of movement      motion                                           Parallel to                                                                            The actuator moves                                                                        Suitable for                                                                              Fabrication                                                                               USSN 09/113,061;                      chip    parallel to the print                                                                     planar     complexity 09/112,818; 09/112,772;               surface head surface. Drop                                                                        fabrication                                                                               Friction   09/112,754; 09/112,811,                       ejection may still be Stiction   09/112,812; 09/112,813                        normal to the                                                                  surface.                                                               Membrane                                                                               An actuator with a                                                                        The effective                                                                             Fabrication                                                                               1982 Howkins USP                      push    high force but small                                                                      area of the                                                                               complexity 4,459,601                                     area is used to push                                                                      actuator   Actuator size                                            a stiff membrane                                                                          becomes the                                                                               Difficulty of                                            that is in contact                                                                        membrane area                                                                             integration in a                                         with the ink.         VLSI process                                     Rotary  The actuator causes                                                                       Rotary levers                                                                             Device     USSN 09/113,097;                              the rotation of some                                                                      may be used to                                                                            complexity 09/113,066; 09/112,818;                       element, such a grill                                                                     increase travel                                                                           May have   09/112,794                                    or impeller                                                                               Small chip area                                                                           Friction at a                                                       requirements                                                                              pivot point                                      Bend    The actuator bends                                                                        A very small                                                                              Requires the                                                                              1970 Kyser et al USP                          when energized.                                                                           change in  actuator to be                                                                            3,946,398                                     This may be due to                                                                        dimensions can                                                                            made from at                                                                              1973 Stemme USP                               differential thermal                                                                      be converted to                                                                           least two  3,747,120                                     expansion, a large motion.                                                                           distinct layers,                                                                          09/112,802; 09/112,778;                       piezoelectric         or to have a                                                                              09/112,779; 09/113,068;                       expansion,            thermal    09/112,780; 09/113,083;                       magnetostriction, or  difference 09/113,121; 091113,128;                       other form of         across the 09/113,127; 09/112,756;                       relative dimensional  actuator   09/112,754; 09/112,811;                       change.                          09/112,812                            Swivel  The actuator swivels                                                                      Allows     Inefficient                                                                               USSN 09/113,099                               around a central                                                                          operation where                                                                           coupling to the                                          pivot. This motion is                                                                     the net linear                                                                            ink motion                                               suitable where there                                                                      force on the                                                        are opposite forces                                                                       paddle is zero                                                      applied to opposite                                                                       Small chip area                                                     sides of the paddle,                                                                      requirements                                                        e.g. Lorenz force.                                                     Straighten                                                                             The actuator is                                                                           Can be used                                                                               Requires careful                                                                          USSN 09/113,122;                              normally bent, and                                                                        with shape balance of 09/112,755                                    straightens when                                                                          memory alloys                                                                             stresses to                                              energized. where the  ensure that the                                                     austenic phase                                                                            quiescent bend                                                      is planar  is accurate                                      Double  The actuator bends                                                                        One actuator                                                                              Difficult to                                                                              USSN 09/112,813;                      bend    in one direction                                                                          can be used to                                                                            make the drops                                                                            09/112,814; 09/112,764                        when one element is                                                                       power two  ejected by both                                          energized, and                                                                            nozzles.   bend directions                                          bends the other way                                                                       Reduced chip                                                                              identical.                                               when another                                                                              size.      A small                                                  element is Not sensitive to                                                                          efficiency loss                                          energized. ambient    compared to                                                         temperature                                                                               equivalent                                                                     single bend                                                                    actuators.                                       Shear   Energizing the                                                                            Can increase the                                                                          Not readily                                                                               1985 Fishbeck USP                             actuator causes a                                                                         effective travel                                                                          applicable to                                                                             4,584,590                                     shear motion in the                                                                       of piezoelectric                                                                          other actuator                                           actuator material.                                                                        actuators  mechanisms                                       Radial  The actuator                                                                              Relatively easy                                                                           High force 1970 Zoltan USP                       con-    squeezes an ink                                                                           to fabricate                                                                              required   3,683,212                             striction                                                                              reservoir, forcing                                                                        single nozzles                                                                            Inefficient                                              ink from a from glass Difficult to                                             constricted nozzle.                                                                       tubing as  integrate with                                                      macroscopic                                                                               VLSI processes                                                      structures                                                  Coil/   A coiled actuator                                                                         Easy to    Difficult to                                                                              USSN 09/112,815;                      uncoil  uncoils or coils                                                                          fabricate as a                                                                            fabricate for                                                                             09/112,808; 09/112,811;                       more tightly. The                                                                         planar VLSI                                                                               non-planar 09/112,802                                    motion of the free                                                                        process    devices                                                  end of the actuator                                                                       Small area Poor out-of-                                             ejects the ink.                                                                           required,  plane stiffness                                                     therefore low                                                                  cost                                                        Bow     The actuator bows                                                                         Can increase the                                                                          Maximum    USSN 09/112,819;                              (or buckles) in the                                                                       speed of travel                                                                           travel is  09/113,096; 09/112,793                        middle when                                                                               Mechanically                                                                              constrained                                              energized. rigid      High force                                                                     required                                         Push-Pull                                                                              Two actuators                                                                             The structure is                                                                          Not readily                                                                               USSN 0/1113,096                               control a shutter.                                                                        pinned at both                                                                            suitable for ink                                         One actuator pulls                                                                        ends, so has a                                                                            jets which                                               the shutter, and the                                                                      high out-of-                                                                              directly push                                            other pushes it.                                                                          plane rigidity                                                                            the ink                                          Curl    A set of actuators                                                                        Good fluid flow                                                                           Design     USSN 09/113,095;                      inwards curl inwards to                                                                           to the region                                                                             complexity 09/112,807                                    reduce the volume                                                                         behind the                                                          of ink that they                                                                          actuator                                                            enclose.   increases                                                                      efficiency                                                  Curl    A set of actuators                                                                        Relatively Relatively large                                                                          USSN 09/112,806                       outwards                                                                               curl outwards,                                                                            simple     chip area                                                pressurizing ink in a                                                                     construction                                                        chamber                                                                        surrounding the                                                                actuators, and                                                                 expelling ink from a                                                           nozzle in the                                                                  chamber.                                                               Iris    Multiple vanes                                                                            High efficiency                                                                           High fabrication                                                                          USSN 09/112,809                               enclose a volume of                                                                       Small chip area                                                                           complexity                                               ink. These            Not suitable for                                         simultaneously        pigmented inks                                           rotate, reducing the                                                           volume between the                                                             vanes.                                                                 Acoustic                                                                               The actuator                                                                              The actuator                                                                              Large area 1993 Hadimioglu et al,                vibration                                                                              vibrates at a high                                                                        can be     required for                                                                              EUP 550,192                                   frequency. physically efficient  1993 Elrod et al, EUP                                    distant from the                                                                          operation at                                                                              572,220                                                  ink        useful                                                                         frequencies                                                                    Acoustic                                                                       coupling and                                                                   crosstalk                                                                      Complex drive                                                                  circuitry                                                                      Poor control of                                                                drop volume                                                                    and position                                     None    In various ink jet                                                                        No moving  Various other                                                                             Silverbrook, EP 0771 658                      designs the actuator                                                                      Parts      tradeoffs are                                                                             A2 and related patent                         does not move.        required to                                                                               applications                                                        eliminate  Tone-jet                                                            moving parts                                     NOZZLE REFILL METHOD                                                           Surface This is the normal                                                                        Fabrication                                                                               Low speed  Thermal ink jet                       tension way that ink jet are                                                                      simplicity Surface tension                                                                           Piezoelectric ink jet                         refilled. After the                                                                       Operational                                                                               force relatively                                                                          USSN 09/112,751;                              actuator is energized,                                                                    simplicity small      09/113,084; 09/112,779;                       it typically returns  compared to                                                                               09/112,8 16; 09/112,819;                      rapidly to its normal actuator force                                                                            09/113,095; 09/112,809;                       position. This rapid  Long refill                                                                               09/112,780; 09/113,083;                       return sucks in air   time usually                                                                              09/113,121; 09/113,122;                       through the nozzle    dominates the                                                                             09/112,793; 09/112,794;                       operating. The ink    total repetition                                                                          09/113,128; 09/113,127;                       surface tension at the                                                                               rate       09/112,756; 09/112,755;                       nozzle then exerts a             09/112,754; 09/112,811;                       small force restoring            09/112,812; 09/112,813;                       the meniscus to a                09/112,814; 09/112,764;                       minimum area. This               09/112,765; 09/112,767;                       force refills the                09/112,768; 09/112,807;                       nozzle.                          09/112,806; 09/112,820;                                                        09/112,821                            Shuttered                                                                              Ink to the nozzle                                                                         High speed Requires   USSN 09/113,066;                      oscillating                                                                            chamber is provided                                                                       Low actuator                                                                              common ink 09/112,818; 09/112,772;               ink     at a pressure that                                                                        energy, as the                                                                            pressure   09/112,815; 09/113,096;               pressure                                                                               oscillates at twice the                                                                   actuator need                                                                             oscillator 09/113,068; 09/112,808                        drop ejection                                                                             only open or                                                                              May not be                                               frequency. When a                                                                         close the  suitable for                                             drop is to be ejected,                                                                    shutter, instead                                                                          pigmented inks                                           the shutter is opened                                                                     of ejecting the                                                     for 3 half cycles:                                                                        ink drop                                                            drop ejection,                                                                 actuator return, and                                                           refill. The shutter is                                                         then closed to prevent                                                         the nozzle chamber                                                             emptying during the                                                            next negative                                                                  pressure cycle.                                                        Refill  After the main                                                                            High speed, as                                                                            Requires two                                                                              USSN 09/112,778                       actuator                                                                               actuator has ejected a                                                                    the nozzle is                                                                             independent                                              drop a second (refill)                                                                    actively   actuators per                                            actuator is energized.                                                                    refilled   nozzle                                                   The refill actuator                                                            pushes ink into the                                                            nozzle chamber. The                                                            refill actuator returns                                                        slowly, to prevent its                                                         return from emptying                                                           the chamber again.                                                     Positive                                                                               The ink is held a                                                                         High refill rate,                                                                         Surface spill                                                                             Silverbrook, EP 0771 658              ink     slight positive                                                                           therefore a                                                                               must be    A2 and related patent                 pressure                                                                               pressure. After the                                                                       high drop  prevented  applications                                  ink drop is ejected,                                                                      repetition rate                                                                           Highly     Alternative for: USSN                         the nozzle chamber                                                                        is possible                                                                               hydrophobic                                                                               09/112,751; 09/112,787;                       fills quickly as      printhead  09/112,802; 09/112,803;                       surface tension and   surfaces are                                                                              09/113,097; 09/113,099;                       ink pressure both     required   09/113,084; 09/112,779;                       operate to refill the            09/113,077; 09/113,061;                       nozzle.                          09/112,818; 09/112,816;                                                        09/112,819; 09/113,095;                                                        09/112,809; 09/112,780;                                                        09/113,083; 09/113,121;                                                        09/113,122; 09/112,793;                                                        09/112,794; 09/113,128,                                                        09/113,127; 09/112,756;                                                        09/112,755; 09/112,754;                                                        09/112,811; 09/112,812;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820; 09/112,821                METHOD OF RESTRICTING BACK-FLOW THROUGH INLET                                  Long inlet                                                                             The ink inlet                                                                             Design     Restricts refill                                                                          Thermal ink jet                       channel channel to the                                                                            simplicity rate       Piezoelectric ink jet                         nozzle chamber is                                                                         Operational                                                                               May result in a                                                                           USSN 09/112,807;                              made long and                                                                             simplicity relatively large                                                                          09/112,806                                    relatively narrow,                                                                        Reduces    chip area                                                relying on viscous                                                                        crosstalk  Only partially                                           drag to reduce inlet  effective                                                back-flow.                                                             Positive                                                                               The ink is under a                                                                        Drop selection                                                                            Requires a Silverbrook, EP 0771 658              ink     positive pressure, so                                                                     and separation                                                                            method (such                                                                              A2 and related patent                 pressure                                                                               that in the quiescent                                                                     forces can be                                                                             as a nozzle run                                                                           applications                                  state some of the ink                                                                     reduced    or effective                                                                              Possible operation of the                     drop already                                                                              Fast refill time                                                                          hydrophobizing                                                                            following:                                    protrudes from the    g, or both) to                                                                            USSN 09/112,751;                              nozzle.               prevent    09/112,787; 09/112,802;                       This reduces the      flooding of the                                                                           09/112,803; 09/113,097;                       pressure in the       ejection   09/113,099; 09/113,084;                       nozzle chamber        surface of the                                                                            09/112,778; 09/112,779;                       which is required to  print head.                                                                               09/113,077; 09/113,061;                       eject a certain                  09/112,816; 09/112,819;                       volume of ink. The               09/113,095; 09/112,809;                       reduction in                     09/112,780; 09/113,083;                       chamber pressure                 09/113,121; 09/113,122;                       refits in a reduction            09/112,793; 09/112,794;                       in ink pushed out                09/113,128; 09/113,127;                       through the inlet.               09/112,756; 09/112,755;                                                        09/112,754; 09/112,811;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;               Baffle  One or more baffles                                                                       The refill rate is                                                                        Design     HP Thermal Ink Jet                            are placed in the                                                                         not as restricted                                                                         complexity Tektronix piezoelectric ink                   inlet ink flow. When                                                                      as the long inlet                                                                         May increase                                                                              jet                                           the actuator is                                                                           method.    fabrication                                              energized, the rapid                                                                      Reduces    complexity                                               ink movement                                                                              crosstalk  (e.g. Tektronix                                          creates eddies which  hot melt                                                 restrict the flow     Piezoelectric                                            through the inlet.    print heads).                                            The slower refill                                                              process is                                                                     unrestricted, and                                                              does not result in                                                             eddies.                                                                Flexible                                                                               In this method                                                                            Significantly                                                                             Not applicable                                                                            Canon                                 flap    recently disclosed                                                                        reduces back-                                                                             to most ink jet                                  restricts                                                                              by Canon, the                                                                             flow for edge-                                                                            configurations                                   inlet   expanding actuator                                                                        shooter thermal                                                                           Increased                                                (Bubble) pushes on a                                                                      ink jet devices                                                                           fabrication                                              flexible flap that    complexity                                               restricts the inlet.  Inelastic                                                                      deformation of                                                                 polymer flap                                                                   results in creep                                                               over extended                                                                  use                                              Inlet filter                                                                           A filter is located                                                                       Additional Restricts refill                                                                          USSN 09/112,803;                              between the ink inlet                                                                     advantage of                                                                              rate       09/113,061; 09/113,083;                       and the nozzle                                                                            ink filtration                                                                            May resulting                                                                             09/112,793; 09/113,128;                       chamber. The filter                                                                       Ink filter may                                                                            complex    09/113,127                                    has a multitude of                                                                        be fabricated                                                                             construction                                             small holes or slots,                                                                     with no                                                             restricting ink flow.                                                                     additional                                                          The filter also                                                                           process steps                                                       removes particles                                                              which may block the                                                            nozzle.                                                                Small inlet                                                                            The ink inlet                                                                             Design     Restricts refill                                                                          USSN 09/112,787;                      compared                                                                               channel to the                                                                            simplicity rate       09/112,814; 09/112,820                to nozzle                                                                              nozzle chamber has    May result in a                                          a substantially       relatively large                                         smaller cross section chip area                                                than that of the      Only partially                                           nozzle, resulting in  effective                                                easier ink egress out                                                          of the nozzle than                                                             out of the inlet.                                                      Inlet   A secondary                                                                               Increases speed                                                                           Requires   USSN 09/112,778                       shutter actuator controls the                                                                     of the ink-jet                                                                            separate refill                                          position of a shutter,                                                                    print head actuator and                                             closing off the ink                                                                       operation  drive circuit                                            inlet when the main                                                            actuator is                                                                    energized.                                                             The inlet is                                                                           The method avoids                                                                         Back-flow  Requires   USSN 09/112,751;                      located the problem of inlet                                                                      problem is careful design                                                                            09/112,802; 09/113,097;               behind the                                                                             back-flow by                                                                              eliminated to minimize                                                                               09/113,099; 09/113,084;               ink-    arranging the ink-    the negative                                                                              09/112,779; 09/113,077;               pushing pushing surface of    pressure   09/112,816; 09/112,819;               surface the actuator between  behind the 09/112,809; 09/112,780;                       the inlet and the     paddle     09/113,121; 09/112,794;                       nozzle.                          09/112,756; 09/112,755;                                                        09/112,754; 09/112,811;                                                        09/112,812; 09/112,813;                                                        09/112,765; 09/112,767;                                                        09/112,768                            Part of the                                                                            The actuator and a                                                                        Significant                                                                               Small increase                                                                            USSN 09/113,084;                      actuator                                                                               Wall of the ink                                                                           reductions in                                                                             in fabrication                                                                            09/113,095; 09/113,122;               moves to                                                                               chamber are                                                                               back-flow can                                                                             complexity 09/112,764                            shut off                                                                               arranged so that the                                                                      be achieved                                                 the inlet                                                                              motion of the                                                                             Compact                                                             actuator closes off                                                                       designs possible                                                    the inlet.                                                             Nozzle  In some    Ink back-flow                                                                             None related to                                                                           Silverbrook, EP 0771 658              actuator                                                                               configurations of                                                                         problem is ink back-flow                                                                             A2 and related patent                 does not                                                                               ink jet, there is no                                                                      eliminated on actuation                                                                              applications                          result in                                                                              expansion or                     Valve-jet                             ink back-                                                                              movement of an                   Tone-jet                              flow    actuator which may                                                             cause ink back-flow                                                            through the inlet.                                                     NOZZLE CLEARING METHOD                                                         Normal  All of the nozzles                                                                        No added   May not be Most ink jet systems                  nozzle  are fired  complexity on                                                                             sufficient to                                                                             USSN 09/112,751;                      firing  periodically, before                                                                      the print head                                                                            displace dried                                                                            09/112,787; 09/112,802;                       the ink has a chance  ink        09/112,803; 09/113,097;                       to dry. When not in              09/113,099; 09/113,084;                       use the nozzles are              09/112,778; 09/112,779;                       sealed (capped)                  09/113,077; 09/113,061;                       against air.                     09/112,816; 09/112,819;                       The nozzle firing is             09/113,095; 09/112,809;                       usually performed                09/112,780; 09/113,083;                       during a special                 09/113,121; 09/113,122;                       clearing cycle, after            09/112,793; 09/112,794;                       first moving the                 09/113,128; 09/113,127;                       print head to a                  09/112,756; 09/112,755;                       cleaning station.                09/112,754; 09/112,811;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820; 09/112,821                Extra   In systems which                                                                          Can be highly                                                                             Requires   Silverbrook, EP 0771 658              power to                                                                               heat the ink, but do                                                                      effective if the                                                                          higher drive                                                                              A2 and related patent                 ink heater                                                                             not boil it under                                                                         heater is  voltage for                                                                               applications                                  normal situations,                                                                        adjacent to the                                                                           clearing                                                 nozzle clearing can                                                                       nozzle     May require                                              be achieved by over-  larger drive                                             powering the heater   transistors                                              and boiling ink at                                                             the nozzle.                                                            Rapid   The actuator is feed                                                                      Does not   Effectiveness                                                                             May be used with: USSN                succession                                                                             in rapid succession.                                                                      require extra                                                                             depends    09/112,751; 09/112,787;               of      In some    drive circuits on                                                                         substantially                                                                             09/112,802; 09/112,803;               actuator                                                                               configurations, this                                                                      the print head                                                                            upon the   09/113,097; 09/113,099;               pulses  may cause heat                                                                            Can be readily                                                                            configuration                                                                             09/113,084; 09/112,778;                       build-up at the                                                                           controlled and                                                                            of the ink jet                                                                            09/112,779; 09/113,077;                       nozzle which boils                                                                        initiated by                                                                              nozzle     09/112,816; 09/112,819;                       the ink, clearing the                                                                     digital logic         09/113,095; 09/112,809;                       nozzle. In other                 09/112,780; 09/113,083;                       situations, it may               09/113,121; 09/112,793;                       cause sufficient                 09/112,794; 09/113,128;                       vibrations to                    09/113,127; 09/112,756;                       dislodge clogged                 09/112,755; 09/112,754;                       nozzles.                         09/112,811; 09/112,813;                                                        09/112,814; 09/112,764;                                                        09/112,765; 09/112,767;                                                        09/112,768; 09/112,807;                                                        09/112,806; 09/112,820;                                                        09/112,821                            Extra   Where an actuator is                                                                      A simple   Not suitable                                                                              May be used with: USSN                power to                                                                               not normally driven                                                                       solution where                                                                            where there is                                                                            09/112,802; 09/112,778;               ink     to the limit of its                                                                       applicable A hard limit to                                                                           09/112,819; 09/113,095;               pushing motion, nozzle        actuator   09/112,780; 09/113,083;               actuator                                                                               clearing may be       movement   09/113,121; 09/112,793;                       assisted by                      09/113,128; 09/113,127;                       providing an                     09/112,756; 09/112,755;                       enhanced drive                   09/112,765; 09/112,767;                       signal to the                    09/112,768; 09/112,807;                       actuator.                        09/112,806; 09/112,820;                                                        09/112,821                            Acoustic                                                                               An ultrasonic wave                                                                        A high nozzle                                                                             High       USSN 09/113,066;                      resonance                                                                              is applied to the ink                                                                     clearing   implementation                                                                            09/112,818; 09/112,772;                       chamber. This wave                                                                        capability can                                                                            n cost if  09/112,815; 09/113,096;                       is of an appropriate                                                                      be achieved                                                                               system does                                                                               09/113,068; 09/112,808                        amplitude and                                                                             May be     not already                                              frequency to cause                                                                        implemented at                                                                            include an                                               sufficient force at                                                                       very low cost in                                                                          acoustic                                                 the nozzle to clear                                                                       systems which                                                                             actuator                                                 blockages. This is                                                                        already include                                                     easiest to achieve if                                                                     acoustic                                                            the ultrasonic wave                                                                       actuators                                                           is at a resonant                                                               frequency of the ink                                                           cavity.                                                                Nozzle  A microfabricated                                                                         Can clear  Accurate   Silverbrook, EP 0771 658              clearing                                                                               plate is pushed                                                                           severely   mechanical A2 and related patent                 plate   against the nozzles.                                                                      clogged nozzles                                                                           alignment is                                                                              applications                                  The plate has a post  required                                                 for every nozzle. A   Moving parts                                             post moves through    are required                                             each nozzle,          There is risk of                                         displacing dried ink. damage to the                                                                  nozzles                                                                        Accurate                                                                       fabrication is                                                                 required                                         Ink     The pressure of the                                                                       May be     Requires   May be used with ink jet              pressure                                                                               ink is temporarily                                                                        effective where                                                                           pressure pump                                                                             covered by USSN                       pulse   increased so that ink                                                                     other methods                                                                             or other   09/112,751; 09/112,787;                       streams from all of                                                                       cannot be used                                                                            pressure   09/112,802; 09/112,803;                       the nozzles. mis      actuator   09/113,097; 09/113,099;                       may be used in        Expensive  09/113,084; 09/113,066;                       conjunction with      Wasteful of                                                                               09/112,778; 09/112,779;                       actuator energizing.  ink        09/113,077; 09/113,061;                                                        09/112,818; 09/112,816;                                                        09/112,772; 09/112,819;                                                        09/112,815; 09/113,096;                                                        09/113,068; 09/113,095;                                                        09/112,808; 09/112,809;                                                        09/112,780; 09/113,083;                                                        09/113,121; 09/113,122;                                                        09/112,793; 09/112,794;                                                        09/113,128; 09/113,127;                                                        09/112,756; 09/112,755;                                                        09/112,754; 09/112,811;                                                        09/112,812; 09/112,813;                                                        09/112,814; 09/112,764;                                                        09/112,765; 09/112,767;                                                        09/112,768; 09/112,807;                                                        09/112,806; 09/112,820;                                                        09/112,821                            Print head                                                                             A flexible `blade` is                                                                     Effective for                                                                             Difficult to use                                                                          Many ink jet systems                  wiper   wiped across the                                                                          planar print                                                                              if print head                                            print head surface.                                                                       head surfaces                                                                             surface is non-                                          The blade is usually                                                                      Low cost   planar or very                                           fabricated from a     fragile                                                  flexible polymer,     Requires                                                 e.g. rubber or        mechanical                                               synthetic elastomer.  parts                                                                          Blade can wear                                                                 out in high                                                                    volume print                                                                   systems                                          Separate                                                                               A separate heater is                                                                      Can be effective                                                                          Fabrication                                                                               Can be used with many ink             ink boiling                                                                            provided at the                                                                           where other                                                                               complexity jets covered by USSN                  heater  nozzle although the                                                                       nozzle clearing       09/112,751; 09/112,787;                       normal drop e-                                                                            methods cannot        09/112,802; 09/112,803;                       ection mechanism                                                                          be used               09/113,097; 09/113,099;                       does not require it                                                                       Can be                09/113,084; 09/113,066;                       The heaters do not                                                                        implemented at        09/112,778; 09/112,779;                       require individual                                                                        no additional         09/113,077; 09/113,061;                       drive circuits, as                                                                        cost in some ink      09/112,818; 09/112,816;                       many nozzles can be                                                                       jet                   09/112,772; 09/112,819;                       cleared    configurations        09/112,815; 09/113,096;                       simultaneously, and              09/113,068; 09/113,095;                       no imaging is                    09/112,808; 09/112,809;                       required.                        09/112,780; 09/113,083;                                                        09/113,121; 09/113,122;                                                        09/112,793; 09/112,794;                                                        09/113,128; 09/113,127;                                                        09/112,756; 09/112,755;                                                        09/112,754; 09/112,811;                                                        09/112,812; 09/112,813;                                                        09/112,814; 09/112,764;                                                        09/112,765; 09/112,767;                                                        09/112,768; 09/112,807;                                                        09/112,806; 09/112,820;                                                        09/112,821                            NOZZLE PLATE CONSTRUCTION                                                      Electro-                                                                               A nozzle plate is                                                                         Fabrication                                                                               High       Hewlett Packard Thermal               formed  separately fabricated                                                                     simplicity temperatures                                                                              Ink jet                               nickel  from electroformed    and pressures                                            nickel, and bonded    are required to                                          to the print head     bond nozzle                                              chip.                 plate                                                                          Minimum                                                                        thickness                                                                      constraints                                                                    Differential                                                                   thermal                                                                        expansion                                        Laser   Individual nozzle                                                                         No masks   Each hole must                                                                            Canon Bubblejet                       ablated or                                                                             holes are ablated by                                                                      required   be individually                                                                           1988 Sercel et al., SPIE,             drilled an intense UV laser                                                                       Can be quite                                                                              formed     Vol. 998 Excimer Beam                 polymer in a nozzle plate,                                                                        fast       Special    Applications, pp. 76-83                       which is typically a                                                                      Some control                                                                              equipment  1993 Watanabe et al.,                         polymer such as                                                                           over nozzle                                                                               required   USP 5,208,604                                 polyimide or                                                                              profile is Slow where                                               polysulphone                                                                              possible   there are many                                                      Equipment  thousands of                                                        required is                                                                               nozzles per                                                         relatively low                                                                            print head                                                          cost       May produce                                                                    thin burrs at                                                                  exit holes                                       Silicon A separate nozzle                                                                         High accuracy                                                                             Two part   K. Bean, IEEE                         micro-  plate is   is attainable                                                                             construction                                                                              Transactions on Electron              machined                                                                               micromachined         High cost  Devices, Vol. ED-25, No.                      from single crystal   Requires   10, 1978, pp 1185-1195                        silicon, and bonded   precision  Xerox 1990 Hawkins et al.,                    to the print head     alignment  USP 4,899,181                                 wafer.                Nozzles may                                                                    be clogged by                                                                  adhesive                                         Glass   Fine glass No expensive                                                                              Very small 1970 Zoltan USP                       capillaries                                                                            capillaries are drawn                                                                     equipment  nozzle sizes                                                                              3,683,212                                     from glass tubing.                                                                        required   are difficult to                                         This method has                                                                           Simple to make                                                                            form                                                     been used for                                                                             single nozzles                                                                            Not suited for                                           making individual     mass                                                     nozzles, but is       production                                               difficult to use for                                                           bulk manufacturing                                                             of print heads with                                                            thousands of                                                                   nozzles.                                                               Monolithic,                                                                            The nozzle plate is                                                                       High accuracy                                                                             Requires   Silverbrook, EP 0771 658              surface deposited as a layer                                                                      (<1 μm) sacrificial layer                                                                         A2 and related patent                 micro-  using standard VLSI                                                                       Monolithic under the  applications                          machined                                                                               deposition Low cost   nozzle plate to                                                                           USSN 09/112,751;                      using VLSI                                                                             techniques. Nozzles                                                                       Existing   form the   09/112,787; 09/112,803;               litho-  are etched in the                                                                         processes can                                                                             nozzle     09/113,077; 09/113,061;               graphic nozzle plate using                                                                        be need    chamber    09/112,815; 09/113,096;               processes                                                                              VLSI lithography      Surface may                                                                               09/113,095; 09/112,809;                       and etching.          be fragile to                                                                             09/113,083; 09/112,793;                                             the touch  09/112,794; 09/113,128;                                                        09/113,127; 09/112,756;                                                        09/112,755; 09/112,754;                                                        09/112,811; 09/112,813;                                                        09/112,814; 09/112,764;                                                        09/112,765; 09/112,767;                                                        09/112,768; 09/112,807;                                                        09/112,806; 09/112,820                Monolithic,                                                                            The nozzle plate is a                                                                     High accuracy                                                                             Requires long                                                                             USSN 09/112,802;                      etched  buried etch stop in                                                                       (<1 μm) etch times 09/113,097; 09/113,099;               through the wafer. nozzles                                                                        Monolithic Requires a 09/113,084; 09/113,066;               substrate                                                                              chambers are etched                                                                       Low cost   support wafer                                                                             09/112,778; 09/112,779;                       in the front of the                                                                       No differential       09/112,818; 09/112,816;                       wafer, and the wafer                                                                      expansion             09/112,772; 09/112,819;                       is thinned from the              09/113,068; 09/112,808;                       back side. Nozzles               09/112,780; 09/113,121;                       are then etched in               09/113,122                                    the etch stop layer.                                                   No nozzle                                                                              Various methods                                                                           No nozzles to                                                                             Difficult to                                                                              Ricoh 1995 Sekiya et al               plate   have been tried to                                                                        become clogged                                                                            control drop                                                                              USP 5,412,413                                 eliminate the         position   1993 Hadimioglu et al EUP                     nozzles entirely, to  accurately 550, 192                                      prevent nozzle        Crosstalk  1993 Elrod et al EUP                          clogging. These       problems   572,220                                       include thermal                                                                bubble mechanisms                                                              and acoustic lens                                                              mechanisms                                                             Trough  Each drop ejector                                                                         Reduced    Drop firing                                                                               USSN 09/112,812                               has a trough through                                                                      manufacturing                                                                             direction is                                             which a paddle                                                                            complexity sensitive to                                             moves. There is no                                                                        Monolithic wicking.                                                 nozzle plate.                                                          Nozzle slit                                                                            The elimination of                                                                        No nozzles to                                                                             Difficult to                                                                              1989 Saito et al                      instead of                                                                             nozzle holes and                                                                          become clogged                                                                            control drop                                                                              USP 4,799,068                         individual                                                                             replacement by a slit position                                         nozzles encompassing many     accurately                                               actuator positions    Crosstalk                                                reduces nozzle        problems                                                 clogging, but                                                                  increases crosstalk                                                            due to ink surface                                                             waves                                                                  DROP EJECTION DIRECTION                                                        Edge    Ink flow is along the                                                                     Simple     Nozzles    Canon Bubblejet 1979                  (`edge  surface of the chip,                                                                      construction                                                                              limited to edge                                                                           Endo et al GB patent                  shooter`)                                                                              and ink drops are                                                                         No Silicon High       2,007,162                                     ejected from the                                                                          etching required                                                                          resolution is                                                                             Xerox heater-in-pit 1990                      chip edge. Good heat  difficult  Hawkins et al USP                                        sinking via                                                                               Fast color 4,899,181                                                substrate  printing   Tone-jet                                                 Mechanically                                                                              requires one                                                        strong     print head per                                                      Ease of chip                                                                              color                                                               handing                                                     Surface Ink flow is along the                                                                     No bulk silicon                                                                           Maximum ink                                                                               Hewlett-Packard TIJ 1982              (`roof  surface of the chip,                                                                      etching required                                                                          flow is    Vaught et al USP                      shooter`)                                                                              and ink drops are                                                                         Silicon can                                                                               severely   4,490,728                                     ejected from the                                                                          make an    restricted USSN 09/112,787,                              chip surface, normal                                                                      effective heat        09/113,077; 09/113,061;                       to the plane of the                                                                       sink                  09/113,095; 09/112,809                        chip.      Mechanical                                                                     strength                                                    Through Ink flow is through                                                                       High ink flow                                                                             Requires bulk                                                                             Silverbrook, EP 0771 658              chip,   the chip, and ink                                                                         Suitable for                                                                              silicon etching                                                                           A2 and related patent                 forward drops are ejected                                                                         pagewidth print       applications                          (`up    from the front                                                                            heads                 USSN 09/112,803;                      shooter`)                                                                              surface of the chip.                                                                      High nozzle           09/112,815; 09/113,096;                                  packing density       09/113,083; 09/112,793;                                  therefore low         09/112,794; 09/113,128;                                  manufacturing         09/113,127; 09/112,756;                                  cost                  09/112,755; 09/112,754;                                                        09/112,811; 09/112,812;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820; 09/112,821                Through Ink flow is through                                                                       High ink flow                                                                             Requires wafer                                                                            USSN 09/112,751;                      chip,   the chip, and ink                                                                         Suitable for                                                                              thinning   09/112,802; 09/113,097;               reverse drops are ejected                                                                         pagewidth print                                                                           Requires   09/113,099; 09/113,084;               (`down  from the rear surface                                                                     heads      special    09/113,066; 09/112,778;               shooter`)                                                                              of the chip.                                                                              High nozzle                                                                               handling   09/112,779; 09/112,818;                                  packing density                                                                           during     09/112,816; 09/112,772;                                  therefore low                                                                             manufacture                                                                               09/112,819;                                              manufacturing         09/113,068;09/112,808;                                   cost                  09/112,780; 09/113,121;                                                        09/113,122                            Through Ink flow is through                                                                       Suitable for                                                                              Pagewidth  Epson Stylus                          actuator                                                                               the actuator, which                                                                       piezoelectric                                                                             print heads                                                                               Tektronix hot melt                            is not fabricated as                                                                      print heads                                                                               require several                                                                           piezoelectric ink jets                        part of the same      thousand                                                 substrate as the      connections to                                           drive transistors.    drive circuits                                                                 Cannot be                                                                      manufactured                                                                   in standard                                                                    CMOS fabs                                                                      Complex                                                                        assembly                                                                       required                                         INK TYPE                                                                       Aqueous,                                                                               Water based ink                                                                           Environmentally                                                                           Slow drying                                                                               Most existing ink jet                 dye     which typically                                                                           friendly   Corrosive  USSN 09/112,751;                              contains: water, dye,                                                                     No odor    Bleeds on  09/112,787; 09/112,802;                       surfactant,           paper      09/112,803; 09/113,097;                       humectant, and        May        09/113,099; 09/113,084;                       biocide.              strikethrough                                                                             09/113,066; 09/112,778;                       Modern ink dyes       Cockles paper                                                                             09/112,779; 09/113,077;                       have high water-                 09/113,061; 09/112,818;                       fastness, light                  09/112,816; 09/112,772,                       fastness                         09/112,819; 09/112,815;                                                        09/113,096; 09/113,068;                                                        09/113,095; 09/112,808;                                                        09/112,809; 09/112,780;                                                        09/113,083; 09/113,121;                                                        09/113,122; 09/112,793;                                                        09/112,794; 09/113,128;                                                        09/113,127; 09/112,756;                                                        09/112,755; 09/112,754;                                                        09/112,811; 09/112,812;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820; 09/112,821                                                         Silverbrook, EP 0771 658                                                       A2 and related patent                                                          applications                          Aqueous,                                                                               Water based ink                                                                           Environmentally                                                                           Slow drying                                                                               USSN 09/112,787;                      pigment which typically                                                                           friendly   Corrosive  09/112,803; 09/112,808;                       contains: water,                                                                          No odor    Pigment may                                                                               09/113,122; 09/112,793;                       pigment, surfactant,                                                                      Reduced bleed                                                                             clog nozzles                                                                              09/113,127                                    humectant, and                                                                            Reduced    Pigment may                                                                               Silverbrook, EP 0771 658                      biocide.   wicking    clog actuator                                                                             A2 and related patent                         Pigments have an                                                                          Reduced    mechanisms applications                                  advantage in reduced                                                                      strikethrough                                                                             Cockles paper                                                                             Piezoelectric ink-jets                        bleed, wicking and               Thermal ink jet (with                         strikethrough.                   significant restrictions)             Methyl  MEK is a highly                                                                           Very fast  Odorous    USSN 09/112,751;                      Ethyl   volatile solvent used                                                                     drying     Flammable  09/112,787; 09/112,802;               Ketone  for industrial printing                                                                   Prints on             09/112,803; 09/113,097;               (MEK)   on difficult surfaces                                                                     various               09/113,099; 09/113,084;                       such as aluminum                                                                          substrates such       09/113,066; 09/112,778;                       cans.      as metals and         09/112,779; 09/113,077;                                  plastics              09/113,061; 09/112,818;                                                        09/112,816; 09/112,772;                                                        09/112,819; 09/112,815;                                                        09/113,096; 09/113,068;                                                        091113,095; 09/112,808;                                                        09/112,809; 09/112,780;                                                        09/113,083; 09/113,121;                                                        09/113,122; 09/112,793;                                                        09/112,794; 09/113,128;                                                        09/113,127; 09/112,756;                                                        09/112,755; 09/112,754;                                                        09/112,811; 09/112,812;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820; 09/112,821                Alcohol Alcohol based inks                                                                        Fast drying                                                                               Slight odor                                                                               USSN 09/112,751;                      (ethanol,                                                                              can be used where                                                                         Operates at                                                                               Flammable  09/112,787; 09/112,802;               2-butanol,                                                                             the printer must                                                                          sub-freezing          09/112,803; 09/113,097;               and     operate at temperatures          09/113,099; 09/113,084;               others) temperatures below                                                                        Reduced paper         09/113,066; 09/112,778;                       the freezing point of                                                                     cockle                09/112,779; 09/113,077;                       water. An example of                                                                      Low cost              09/113,061; 09/112,818;                       this is in-camera                09/112,816; 09/112,772;                       consumer                         09/112,819; 09/112,815;                       photographic                     09/113,096; 09/113,068;                       printing.                        09/113,095; 09/112,808;                                                        09/112,809; 09/112,780;                                                        09/113,083; 09/113,121;                                                        09/113,122; 09/112,793;                                                        09/112,794; 09/113,128;                                                        09/113,127; 09/112,756;                                                        09/112,755; 09/112,754;                                                        09/112,811; 09/112,812;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820; 09/112,821                Phase   The ink is solid at                                                                       No drying  High viscosity                                                                            Tektronix hot melt                    change  room temperature,                                                                         time- ink  Printed ink                                                                               piezoelectric ink jet                 (hot melt)                                                                             and is melted in the                                                                      instantly  typically has a                                                                           1989 Nowak USP                                print head before                                                                         freezes on the                                                                            `waxy` feel                                                                               4,820,346                                     jetting. Hot melt inks                                                                    print medium                                                                              Printed pages                                                                             USSN 09/112,751;                              are usually wax                                                                           Almost any may `block`                                                                               09/112,787; 09/112,802;                       based, with a melting                                                                     print medium                                                                              Ink        09/112,803; 09/113,097;                       point around 80° C.                                                                can be used                                                                               temperature                                                                               09/113,099; 09/113,084;                       After jetting the ink                                                                     No paper   may be above                                                                              09/113,066; 09/112,778;                       freezes almost                                                                            cockle occurs                                                                             the curie point                                                                           09/112,779; 09/113,077;                       instantly upon                                                                            No wicking of permanent                                                                              09/113,061; 09/112,818;                       contacting the print                                                                      occurs     magnets    09/112,816; 09/112,772;                       medium or a transfer                                                                      No bleed   Ink heaters                                                                               09/112,819; 09/112,815;                       roller.    occurs     consume    09/113,096; 09/113,068;                                  No         power      09/113,095; 09/112,808;                                  strikethrough                                                                             Long warm-up                                                                              09/112,809; 09/112,780;                                  occurs     time       09/113,083; 09/113,121;                                                        09/113,122; 09/112,793;                                                        09/112,794; 09/113,128;                                                        09/113,127; 09/112,756;                                                        09/112,755; 09/112,754;                                                        09/112,811; 09/112,812;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820; 09/112,821                Oil     Oil based inks are                                                                        High solubility                                                                           High viscosity:                                                                           USSN 09/112,751;                              extensively used in                                                                       medium for this is a  09/112,787; 09/112,802;                       offset printing. They                                                                     some dyes  significant                                                                               09/112,803; 09/113,097;                       have advantages in                                                                        Does not   limitation for                                                                            09/113,099; 09/113,084;                       improved   cockle paper                                                                              use in ink jet,                                                                           09/113,066; 09/112,778;                       characteristics on                                                                        Does not wick                                                                             which usually                                                                             09/112,779; 09/113,077;                       paper (especially no                                                                      through paper                                                                             require a low                                                                             09/113,061; 09/112,818;                       wicking or cockle).   viscosity. 09/112,816; 09/112,772;                       Oil soluble dies and  Some short 09/112,819; 09/112,815;                       pigments are          chain and  09/113,096; 09/113,068;                       required.             multi-breached                                                                            09/113,095; 09/112,808;                                             oils have a                                                                               09/112,809; 09/112,780;                                             sufficiently                                                                              09/113,083; 09/113,121;                                             low viscosity.                                                                            09/113,122; 09/112,793;                                             Slow drying                                                                               09/112,794; 09/113,128;                                                        09/113,127; 09/112,756;                                                        09/112,755; 09/112,754;                                                        09/112,811; 09/112,812;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820; 09/112,821                Micro-  A microemulsion is a                                                                      Stops ink bleed                                                                           Viscosity  USSN 09/112,751;                      emulsion                                                                               stable, self forming                                                                      High dye   higher than                                                                               09/112,787; 09/112,802;                       emulsion of oil,                                                                          solubility water      09/112,803; 09/113,097;                       water, and surfactant.                                                                    Water, oil, and                                                                           Cost is slightly                                                                          09/113,099; 09/113,084;                       The characteristic                                                                        amphiphilic                                                                               higher than                                                                               09/113,066; 09/112,778;                       drop size is less than                                                                    soluble dies                                                                              water based                                                                               09/112,779; 09/113,077;                       100 nm, and is                                                                            can be used                                                                               ink        09/113,061; 09/112,818;                       determined by the                                                                         Can stabilize                                                                             High surfactant                                                                           09/112,816; 09/112,772;                       preferred curvature of                                                                    pigment    concentration                                                                             09/112,819; 09/112,815;                       the surfactant.                                                                           suspensions                                                                               required   09/113,096; 09/113,068;                                             (around 5%)                                                                               09/113,095; 09/112,808;                                                        09/112,809; 09/112,780;                                                        09/113,083; 09/113,121;                                                        09/113,122; 09/112,793;                                                        09/112,794; 09/113,128;                                                        09/113,127; 09/112,756;                                                        09/112,755; 09/112,754;                                                        09/112,811; 09/112,812;                                                        09/112,813; 09/112,814;                                                        09/112,764; 09/112,765;                                                        09/112,767; 09/112,768;                                                        09/112,807; 09/112,806;                                                        09/112,820; 09/112,821                __________________________________________________________________________ 

We claim:
 1. A portable camera system comprising:an image sensor device for sensing an image; a processing means for processing said sensed image; a print media supply means provided for the storage of print media in a roll form; a print head for printing said sensed image on print media stored internally to said camera system; a cutter mechanism for cutting said printed sensed images comprising:a worm screw extending the length of said printed sensed images; a worm gear attached to said worm screw and adapted to be driven the length of said printed sensed image, said worm gear including a cutting blade for cutting said print media into separate sheets.
 2. A portable camera system as claimed in claim 1 wherein said cutting blade comprises a rotatable wheel having a sharpened outer edge.
 3. A portable camera system as claimed in claim 1 further comprising a cogged wheel having a series of usage indicators printed on one surface thereof and wherein said worm gear includes a lever arm and the traversal of said worm gear along the length of said printed sensed image results in the engagement of said lever arm with said cogged wheel print indicator so as to rotate said cogged wheel print indicator so that it maintains a current indication of the number of images printed out on said print media.
 4. A portable camera system as claimed in claim 3 further comprising a pawl mechanism which interacts with the coggs of said cogged wheel print indicator in the form of a rachet and pawl mechanism.
 5. A portable camera system as claimed in claim 3 wherein said lever arm includes a flexible portion for engagement with said cogged wheel print indicator. 